docs(android): the identity is read back, not declared twice

android-tier.md carried a warning block telling the reader not to use
run:device or deploy-device, and offered a manual sequence instead.
Both are wrong now: the tasks are the way in, and the warning would
read as a live hazard. It becomes a note about what changed, and the
manual sequence stays as the smallest thing that works when you want no
script between you and adb.

"The identity is declared twice" was the section this file had carried
for five phases saying nothing enforced that the two ids agree. It
describes the enforcement now, plus what APP_ID means since it stopped
being a setting it never was.

NOTES.md takes the four measurements: that the uninstall existed only
to cover a missing -r (which is what makes deleting it a fix rather
than a trade), that the emulator tasks installed on a phone, what
reading the id back costs, and the boot-wait race filed as #162.

.pi/skills/yellowjacket-dev/SKILL.md

@@ -195,6 +195,12 @@ Two rules about climbing:
 - **Do not write an e2e spec first.** Drive the flow by hand, then
   promote it with `/e2e`. Specs written blind assert on selectors that
   do not exist.
+- **Not every view has a nav item.** Since #25 the destinations are
+  configurable, Autotag is hidden by default and Downloads is absent
+  until a download client exists — so `getByTestId('nav-<view>')` waits
+  30 s for a locator that will never resolve. `navigateTo(page, view)`
+  (`e2e/support/fixtures.ts`) dispatches the app's own `navigate` event.
+  Click the nav item when the *nav* is what the spec is about.
 
 Before a commit, the gate is `make lint`, `make test`, `make ui-test`,
 `make bindings-check`, `make css-check` and — from `frontend/` —

.pi/skills/yellowjacket-dev/references/android-tier.md

@@ -194,9 +194,13 @@ like the app's fault and none is:
 |---|---|---|
 | x86_64 | modernc's raw `lstat` vs seccomp | SIGSYS, syscall 6 |
 | arm64, translated | Go reads `ID_AA64ISAR0_EL1` | SIGILL |
-| arm64, real device | — | unverified, still |
+| arm64, real device | **runs** (2026-08-20) | — |
 
-**A physical arm64 device remains the only verification path.**
+**A physical arm64 device remains the only verification path**, and it
+has now been walked: a Light Phone III (TLP301, Android 14 / SDK 34,
+arm64-v8a, WebView Chrome 113 at 424x439). The app builds, installs,
+launches and stays up; `make android-smoke SECONDS=60` passes on it.
+What that run *found* is the lifecycle fault below.
 
 ### What was fixed to get here
 
@@ -210,6 +214,11 @@ no-op. `backend/system` gained no import of the Wails application
 package, which matters for the same reason `backend/events` is split by
 the `indexbuild` tag.
 
+**And `main()` is now latched to one run per process** (#52). That is
+the second `os.Exit(1)` in this file's history and it had the same
+signature as the first, which is the argument for #160: both were named
+exactly by an `slog` line that went to `/dev/null`.
+
 ### What is still not done
 
 The shell is still a desktop shell, and the x86_64 half of the APK is
@@ -249,10 +258,25 @@ one.
 `build/android/Taskfile.yml` ships more than the Makefile wraps, and
 they are the right thing to reach for when you want something one-off:
 
+> **These four were unsafe until #159 and are now the way in.** All of
+> them began with `adb uninstall {{.APP_ID}}`, where `APP_ID` defaulted
+> to `app.yellowjacket` — the **release** id — while `run` and
+> `run:device` build the **debug** variant, whose id is
+> `app.yellowjacket.dev`. So they uninstalled the user's app, taking
+> the library with it, installed a different package, and then failed
+> to launch the one they had removed.
+>
+> They share `scripts/android-deploy.sh` now, which **never**
+> uninstalls (`install -r`, and a changed signing certificate is
+> reported with the command rather than acted on), reads the package id
+> back out of the built APK, and refuses a target that is not the kind
+> the task names. There is nothing left to avoid; the manual sequence
+> below is kept because it is still the smallest thing that works.
+
 ```
 wails3 task android:run              # debug build + emulator install + launch
-wails3 task android:run:device       # same, first connected physical device
-wails3 task android:deploy-device    # production APK to a device
+wails3 task android:run:device       # debug build + install + launch on a phone
+wails3 task android:deploy-device    # release build, same
 wails3 task android:bundle:fat       # AAB, for a Play Store upload
 wails3 task android:studio           # open build/android/ in Android Studio
 wails3 task android:device:list
@@ -260,6 +284,16 @@ wails3 task android:logs:all
 wails3 task android:clean
 ```
 
+**`run` and `deploy-emulator` mean the emulator, and now say so to
+adb.** They used a bare `adb install`, which with exactly one device
+attached picks that device whatever it is — so with a phone plugged in
+and no emulator running, the task whose summary reads "in the Android
+Emulator" installed on the phone. They pass `--target emulator` and
+refuse with `make android-emulator` as the remedy.
+
+**`DEVICE_ID=<serial>` still names a device, and several attached
+devices is now an error rather than a silent pick of the first.**
+
 Two are deliberately **not** wrapped. `android:logs` greps logcat for
 `(Wails|yellowjacket)`, which catches the `WailsBridge` tag but misses
 the app's own process tag (`app.yellowjacket` — lowercase, so `Wails`
@@ -269,16 +303,51 @@ instead. And `ensure-emulator` boots whatever `-list-avds | tail -1`
 returns, with no pidfile and no boot wait, so it cannot be stopped or
 sequenced.
 
-## The identity is declared twice
+## The identity is read back from the APK
 
+It used to be **declared twice**, and that is what #159 was.
 `applicationId` in `build/android/app/build.gradle` is what Gradle
-installs. `APP_ID` in `build/android/Taskfile.yml` is what every
-adb-driven task uninstalls, launches and filters. **Nothing enforces
-that they agree**, and `ANDROID.md`'s advice to set `APP_ID` in
-`build/config.yml` does not work in beta.8 — `wails3 task` never reads
-that file (verified with `--dry`), and even when set it feeds only the
-adb commands, never Gradle. Change both or the official `run`/`deploy`
-tasks address a package that is not installed.
+installs; `APP_ID` in `build/android/Taskfile.yml` was what every
+adb-driven task uninstalled, launched and filtered, and nothing
+enforced that they agree. They did not: the debug buildType carries
+`applicationIdSuffix ".dev"`, so every task that assembles a debug APK
+addressed the release id. This file flagged the hazard for five phases
+and it cashed out twice — once as a wrong `am start`, once as an
+uninstall of the user's library.
+
+**`scripts/android-pkgid.sh` is the one answer now.** It prints the
+package id an APK declares (`aapt2 dump packagename`, falling back to
+`aapt dump badging`), and the deploy path installs and launches *that*.
+The APK is the authority because the task that installs it has just
+built it: whatever Gradle resolved the applicationId to, suffixes and
+flavours included, is in the file, and no default can disagree with it.
+An APK it cannot read is a hard failure, never a fallback to a written
+down default — guessing is the bug.
+
+**`APP_ID` survives as an assertion, not a setting**, and has no
+default. `wails3 task android:run APP_ID=app.yellowjacket` says "this
+build had better declare that id" and is refused, naming both, *before*
+anything is installed or a device is even chosen. It could never have
+been a setting: `ANDROID.md`'s advice to put it in `build/config.yml`
+does not work in beta.8 — `wails3 task` never reads that file (verified
+with `--dry`) — and even when set it fed only the adb commands, never
+Gradle.
+
+`scripts/android-emulator.sh` derives `PKG` the same way, from
+`bin/yellowjacket.apk` when one is built, so `make android-install`,
+`android-launch`, `android-logs` and `android-smoke` follow whichever
+variant is actually in `bin/`. `YJ_ANDROID_PKG` still overrides, and
+the old literal survives only for a tree with no APK built yet.
+
+**The uninstall is gone and is not coming back.** It existed to make
+the bare `install` on the next line work at all — without `-r` Android
+refuses an install over an existing package — so `install -r` removes
+the *reason* for it rather than merely removing it. What is left is the
+one case an uninstall really is the remedy, a changed signing
+certificate, and that is exactly the case where performing it silently
+costs the user their library. So it is named and not done, which is the
+answer `scripts/android-emulator.sh` had already reached for
+`make android-install`.
 
 Related, and it will bite once: the launcher activity is
 `com.wails.app.MainActivity` and the applicationId is
@@ -287,6 +356,27 @@ resolves the leading dot against the *applicationId* and fails with a
 class-not-found that reads like a broken build. Always the
 fully-qualified form.
 
+**`wails3 task android:run:device` is the way to put a debug build on a
+real device**, since #159. What #52 used, before it was safe, was the
+longer form, and it is still the smallest thing that works if you want
+no script between you and adb:
+
+```bash
+wails3 task android:build ARCH=arm64 && wails3 task android:assemble:apk
+adb install -r bin/yellowjacket.apk      # -r, never uninstall
+adb shell am start -n app.yellowjacket.dev/com.wails.app.MainActivity
+```
+
+The id in that last line is the one thing to keep an eye on by hand —
+`./scripts/android-pkgid.sh bin/yellowjacket.apk` is what the tasks ask,
+and it is a good habit before any `am start` written out in full.
+
+`YJ_ANDROID_PKG=app.yellowjacket.dev` still overrides what
+`scripts/android-emulator.sh` — and therefore `make android-smoke`,
+`android-logs`, `android-launch` — addresses, but it is rarely needed
+now: that default is read from `bin/yellowjacket.apk`, so it already
+follows whichever variant was built last.
+
 ## What only a device can answer
 
 The emulator cannot run this app (three separate reasons, none of them
@@ -311,6 +401,91 @@ system bars, the back gesture, focus and audio interruptions,
 permission dialogs, the keyboard — not about what the app draws. The
 drawing is what the other five tiers already cover.
 
+**The third such fault was the activity lifecycle** (#52), and it is
+the one to re-check after touching `main()`, `WailsBridge` or
+`MainActivity`. Android destroys and recreates an activity **without
+restarting the process**, and Wails' `nativeInit` — which
+`MainActivity.onCreate` calls — runs `go mainFunc()` every time. So
+Go's `main()` ran again on a live app, `app.Run()` refused (`a.starting`
+is still true behind Android's `select{}`), and the `os.Exit(1)` under
+it took the healthy first app down with it.
+
+### The lifecycle check, and how to trigger it on demand
+
+This is the regression guard for #52 on this tier, because no other
+tier runs `main()` on Android at all. The Go-side guard
+(`TestMainClaimsBeforeItDoesAnything`) catches work creeping above the
+latch; only the device catches the latch not working.
+
+**Trigger a relaunch with a configuration change the manifest does not
+declare.** `AndroidManifest.xml` lists
+`orientation|screenSize|keyboardHidden|uiMode`, so those are handled
+in-place and are *not* triggers. `fontScale` is not listed, and it is a
+one-liner:
+
+```bash
+adb shell settings put system font_scale 1.15   # restore the old value after
+```
+
+That is the same in-process destroy/recreate that "Don't keep
+activities", a locale change and a memory trim produce, but on demand.
+
+**"Don't keep activities" is the report's own lever and did not work on
+this device**: `settings put global always_finish_activities 1` reads
+back as `1`, `am set-always-finish-activities` does not exist on this
+build, and the activity was never finished on backgrounding. Do not
+spend an afternoon on it; use the config change.
+
+**The assertion is the pid, and the tell is two bridge inits in one.**
+
+```bash
+adb logcat -d | grep -E "Wails bridge initialized|has died|finishDrawing of relaunch"
+```
+
+Healthy is one pid appearing twice — the process surviving the
+recreation:
+
+```
+I/WailsBridge(28420): Wails bridge initialized
+I/WailsBridge(28420): Wails bridge initialized     <- same pid, recreated
+```
+
+Broken is that pair followed within a second by:
+
+```
+I/WindowManager: finishDrawing of relaunch: Window{...MainActivity} 603ms
+I/ActivityManager: Process app.yellowjacket.dev (pid 22956) has died: fg  TOP
+W/ActivityTaskManager: Force removing ActivityRecord{...}: app died, no saved state
+```
+
+Two things about reading that. **`has died: fg  TOP` is not a memory
+kill** — the system does not reclaim the foreground process, so this is
+the app leaving of its own accord. And there is **no crash record
+anywhere**: `logcat -b crash` is empty, no `AndroidRuntime`, no
+`libc: Fatal signal`, no tombstone. That is the `os.Exit` signature,
+and it is why "the system killed it" is the wrong first hypothesis.
+
+**Surviving is only half of it — check the recreated WebView is still
+wired to the running app.** A plausible-looking fix (making
+`WailsBridge.initialized` static, so the second `nativeInit` is skipped)
+keeps the process alive and silently breaks this, because `nativeInit`
+is also what re-points the JNI reference at the new bridge. Go would go
+on executing JavaScript against the destroyed activity's WebView: the
+app opens, renders, and never receives another backend event.
+
+Ask the page, after a relaunch and a resume:
+
+```bash
+make android-inspect
+make android-eval EXPR='(()=>{window.__probe=[];const o=window._wails.dispatchWailsEvent.bind(window._wails);window._wails.dispatchWailsEvent=(e)=>{window.__probe.push(e&&e.name);return o(e)};return "ok"})()'
+# background and foreground the app, then:
+make android-eval EXPR='JSON.stringify(window.__probe)'
+```
+
+A healthy build answers with events from the live services —
+`["IndexStatusChanged","JobsChanged","JobsChanged","android:storageAccess"]`.
+`[]` means the bridge reference is stale.
+
 ## Asking the device, not just looking at it
 
 A real phone can be inspected, and that turns this tier from "reported

.planning/NOTES.md

@@ -3696,3 +3696,549 @@ as a tidy-up, a change nothing on a desktop renders differently.
 Related: a width-gated decision **is** testable at both tiers, which is
 why #61's phone mini player is a `matchMedia` stub in the component test
 and needs nothing special.
+
+## A default that is an *absent* key survives an existing seed (2026-08-19)
+
+The skill warns that a seed freezes every default it has already
+persisted, so changing one in `backend/config` is invisible against an
+existing `YJ_HOME` while CI, which seeds by running the app, tests the
+new one. That warning is about defaults stored as *values*.
+
+#25's Autotag-hidden default is stored as the **absence of a key**:
+`GeneralConfig.ViewVisibility` is a map, an id it does not mention takes
+`backend/config.Views`' answer, and only what the user changed is ever
+written. So a seed built before the feature existed showed the new
+default immediately — verified against `.dev/seeds/default.tar`, whose
+`config.toml` has no `[General.ViewVisibility]` table at all, and whose
+sidebar came up without Autotag on the first launch of the new binary.
+After toggling it on and off again the file carries exactly one line,
+`autotag = false`.
+
+The general form is worth keeping: **a default expressed as a zero value
+needs a re-seed to observe; a default expressed as an absent key does
+not**, and it needs no migration for existing installs either. It is the
+same property that makes removing a view later free (an unknown key is
+dropped on load), which is what the `#25 → #27` ordering on #73 rests on.
+
+## A spec cannot assume a destination has a nav item (2026-08-19)
+
+Since #25, `getByTestId('nav-<view>')` is not a reliable way to reach a
+view: Autotag is hidden by default and Downloads is absent without a
+download client, so four existing specs failed on a 30 s timeout waiting
+for a locator that will never resolve. `navigateTo(page, view)` in
+`e2e/support/fixtures.ts` dispatches the app's own `navigate` event
+instead, which is what every nav item, card and detail view dispatches —
+so it is the mechanism and not a test-only door.
+
+Use the nav item when the *nav* is the subject, and `navigateTo` when
+the view is.
+
+## `config-section .header` is ambiguous once a job exists (2026-08-19)
+
+#27 embeds `<job-panel>` inside four Settings sections, and a panel with
+any job in it also mounts a `job-details-drawer` — whose own header
+carries the class `.header`. So `config-page config-section .header`,
+which `settings-reach.spec.ts` had used since plan 007, resolves to two
+elements and fails Playwright's strict mode the moment a scan has run.
+
+Two things follow. A spec asserting on a section's *disclosure* should
+locate it by role and name (`getByRole('button', {name: heading})`) or
+scope per section and take `.first()`, not by that class. And this is a
+worked example of the more general trap: a class name is not a
+selector's contract, and a component that embeds another inherits its
+class names into every ancestor query.
+
+It also only appears in a suite that has *done* something — the
+sections are empty on a fresh app, so this cannot be reproduced by
+opening Settings and looking.
+
+**And it appears on the second engine, not the first.** CI runs
+chromium then webkit against **one app**, so a spec that scans in the
+chromium pass leaves a finished job the webkit pass then trips over.
+Three specs used that selector; two failed locally and the third
+(`failure-voice.spec.ts`) was green on chromium and red on webkit in
+the same run. Reproducing it locally is running the suite twice against
+one `make dev-headless` — which is worth doing for any change that
+leaves state behind, since it is the only place a cross-engine order
+dependency shows up.
+
+## `scrollWidth` counts the left padding and not the right (measured 2026-08-20)
+
+The obvious predicate for "does this flex row fit" is
+`el.scrollWidth <= el.clientWidth`, and on a box with symmetric gutters
+it **under-reports by one gutter**. `scrollWidth` is the extent of the
+scrollable content area, which includes `padding-left` and excludes
+`padding-right`; `clientWidth` includes both. So a child may end up to
+`padding-right` past where content is allowed to go while the box
+reports a perfect fit.
+
+Measured on the top bar (`padding: 0 2em`) at 700x600 with a long-titled
+scan staged: `clientWidth 700`, `scrollWidth 700` — and
+`job-indicator`'s right edge at 700 against a content edge of 668, i.e.
+sitting in the whole right gutter. `#143`'s first fix passed its own
+measurement and left the indicator visibly jammed against the window
+edge.
+
+The predicate `services/top-bar-fit.ts` uses instead is the one its
+spec asserts: no in-flow child's rect outside the parent's *content*
+box, both edges, with half a pixel of slack for fractional flex widths.
+
+This is the same family as #69's title trap — the measurement easiest to
+reach for is the one that cannot see the failure — and it is worth
+knowing before writing the next one of these: **the fit test and the
+assertion that proves it should be the same test.** It was found only
+because `top-bar-fit.spec.ts` measures per child rather than asserting
+on the container, which is exactly why #69 needed
+`header-action-overflow.spec.ts`.
+
+## The top bar's overflow is 11px idle and 262px while working (measured 2026-08-20)
+
+#143 was filed as "11px at 600x600" and re-measured as 171. Both are the
+same defect seen with different jobs running: `job-indicator` is
+`hidden` when idle, ~144px wide showing "Scanning Music", and **235px**
+showing a real library's scan title ("Scanning Music from the external
+drive"), because the label is capped at 12rem and gets there.
+
+Swept against the running app with that job staged, `header.top-bar`
+client vs scroll:
+
+| width | idle | with the long-titled scan |
+|---|---|---|
+| 320, 390, 599 | fits | fits (the phone rules drop the filter and the label) |
+| 600 | 611 | **862** |
+| 700 | fits | 862 |
+| 800 | fits | 862 |
+| 899 | fits | 899 (fits) |
+| 900 | fits | 946 |
+| 1100, 1440 | fits | fits |
+
+Two things worth keeping. The band is **600–610 idle and 600–900 while
+working**, so "a narrow corner" and "the header is crowded from 900
+down" are both true and the difference is entirely what is in flight —
+which is the case a seeded, settled app can never show you. And 899
+fits while 900 does not, because `nav-history` appears at 900: the worst
+width for the header is not the narrowest one, the same way 900 rather
+than 800 is the worst width for the content area.
+
+Staging it is `/__test/emit` with a `JobsChanged` snapshot; a job with
+`state: "running"` never completes, so it stays up until an empty
+snapshot is emitted, which is what makes an idle re-measurement look
+like the fix not working.
+
+## Two repaint mechanisms, and neither is pinned alone (measured 2026-08-20)
+
+`CLAUDE.md` already states the rule — *a virtualized list repaints only
+when you tell it to, and the accidental way you were telling it may be
+the thing you are about to delete* — found in `artists-view` and
+`genres-view`. `queue-panel` is a second instance with numbers, and the
+numbers are the part worth keeping.
+
+It repaints its rows **two** ways:
+
+- `onSelectionChanged()` calls `virtualizer.requestUpdate()`, which is
+  the intended one and the one `track-list` has always had;
+- `.keyFunction=${(track) => track.id}` is a **per-render arrow**, so it
+  is a changed property on every host update and repaints the rows by
+  itself.
+
+Removing *either* alone changes nothing observable. That is why #43
+could not be settled by reading the code: the hypothesis in its Findings
+(the repaint is missing) was checkable, false, and would have looked
+identical either way.
+
+Removing **both** does not break selection either — it delays it. Time
+from click to `aria-selected`, three clicks each:
+
+| build | ms to highlight |
+|---|---|
+| healthy | 5, 16, 17 |
+| both mechanisms removed | 134, 3,866, 5,816 |
+
+The highlight arrives on whatever unrelated render happens next (the
+player's 1 Hz position report is the usual candidate). **Four seconds is
+indistinguishable from broken to a user, and invisible to a spec** —
+`expect.poll`'s default 5 s timeout passes the degraded build on every
+assertion. `queue-selection.spec.ts` bounds its selection assertions at
+500 ms for that reason, which is ~30x the healthy case and an order of
+magnitude under the degraded one.
+
+The general form, for the next spec about anything push-driven: **a poll
+generous enough to be stable is generous enough to miss a latency
+regression entirely.** If "late" is a failure mode worth having, the
+timeout has to say so.
+
+## A hit-scan says how much of a row is not selectable (measured 2026-08-20)
+
+`explore-link` stops the click's propagation on purpose — "the row must
+not also treat it as a selection" — so a click on a track, album or
+artist *name* navigates and selects nothing. That is app-wide and
+deliberate, and the useful question about any given list is how much of
+its row it costs.
+
+Asking `elementFromPoint` what is under each x across a row, at three
+heights:
+
+| list | link coverage |
+|---|---|
+| queue panel | 12% |
+| track list | 21% |
+
+This killed a fix in progress. #43 reads as "selection is broken in the
+queue panel, and fine in the track list", the obvious mechanism is that
+the queue's narrow rows are mostly name, and it is **wrong**: the panel
+is *less* link-covered than the list it is being compared against. The
+scan takes a minute and is worth running before demoting anybody's links
+— `explore-album-details`'s tracklist (number / title / artist /
+duration) is the one that plausibly *is* mostly link, and is the one
+#5 is about to add selection to.
+
+## A layout is still moving when a guard says it has arrived (measured 2026-08-20)
+
+`album-dropdown.spec.ts` failed with `Expected 80, Received 10` twice
+over two sessions, and #133 already strengthened its guard from
+"scrollable at all" to "has at least the range the assertion needs".
+That was necessary and could not be sufficient, and the reason is
+structural rather than a matter of thresholds: **a guard and the write
+it guards are separate CDP round trips**, so the page is free to
+re-lay-out between them. Polling harder cannot close a window between
+two moments; only removing the window can.
+
+Measured directly, sampling `scrollHeight - clientHeight` on
+`.grid-scroll-container` every frame across a 1440x900 → 900x600 resize,
+three runs:
+
+| t (ms) | range |
+|---|---|
+| 0 | 0 |
+| 1 | **88** |
+| 8–14 | 330 (settled) |
+
+88 satisfies a guard asking for 80 and is not the settled value, so the
+guard can pass while the grid is one layout pass from done. Under
+full-suite load the transient is worse — the observed failure had 10 —
+which is why it shows up on the second run of a suite and not in ten
+consecutive runs of the file alone (0/10 both before and after the fix).
+
+The shape to write instead: **one page-side call that performs the
+action and returns what it observes**, with `expect.poll` retrying
+*that*. `scrollTo()` sets `scrollTop` and returns `scrollTop`, so the
+assertion is about what the grid did rather than about what it was
+ready to do. `layout-overflow.spec.ts`'s sidebar probe already had the
+fused half and was missing the retry; it has both now.
+
+Worth generalising: a spec that resizes and then measures is asserting
+about a moving target for the next dozen frames. Fuse, then poll.
+
+## "The first N tracks" is not a way to ask for an ordinary one (2026-08-20)
+
+`queue-selection.spec.ts` staged its queue from the first few rows of
+`library.Library.GetTracks(0)` and clicked a track *name*, which
+`explore-link` routes to that track's **album** page. Four tracks in the
+fixture library have no album at all — `01 Tone A`, `02 Tone B`,
+`Title Only`, `no-tags-at-all` — and a name with nothing to route to
+renders as **plain text**, not as a link.
+
+Two things follow, and the second is the sharper one.
+
+**The order is the scan's.** `GetTracks` returns `audio_files.id` order,
+i.e. the order the scan inserted rows, which depends on concurrency and
+directory traversal. Locally the first eight are all from two proper
+albums, so the spec passed twice over; CI rebuilds its seed with a real
+scan, got a different eight, and failed on both engines. This is the
+same family as "a seed freezes every default it has already persisted" —
+the fixture library is not a list, it is a *set* with an incidental
+order, and no spec should depend on that order.
+
+**A loose locator hid it.** The row was located with
+`.locator('.explore-link').first()`, and a row has two — the title and
+the artist. When the title is plain text, `first()` silently resolves to
+the **artist** link, so the click went somewhere real and the assertion
+was about a destination the test had not exercised. `.track-title
+.explore-link` is the locator that says which one it means; the loose
+one turned a fixture problem into a mystery.
+
+The general rule for this repo's fixture library: it is deliberately
+full of edge cases (untagged, unicode, duplicates, extremes), so a spec
+that wants an *ordinary* track has to **say so** — filter on the
+property it depends on rather than slicing.
+## A nested rule starting with an element name is dropped on the phone (2026-08-20)
+
+`CLAUDE.md` records that the device renders in **Chrome 113**, which
+does not have relaxed CSS nesting (Chrome 120). The consequence is
+sharper than "some syntax is unavailable": a nested rule whose selector
+begins with a bare identifier is not a parse error you would notice, it
+is **silently dropped**.
+
+Three such rules were live in `frontend/index.css`, all inside
+`.bottom-bar`, and all therefore dead on the phone and only on the
+phone:
+
+```css
+.bottom-bar {
+    #track-info { p { … } }   /* the metadata's ellipsis */
+    now-playing { overflow: hidden; }
+    audio-player { margin: 0.5em 1em; }
+}
+```
+
+The first is the interesting one: it is the *ellipsis* on the bottom
+bar's track title and artist, so on the device that text has never
+truncated — the same class of fault as `now-playing`'s marquee, whose
+`text-overflow` sat on the wrong box and had never produced an ellipsis
+in any mode. Both are invisible to every assertion and visible in a
+screenshot.
+
+`& p`, `& now-playing`, `& audio-player` are valid in both, so the fix
+is one character per rule. What is worth keeping is the rule of thumb:
+**inside a nested block, always write `&`** — and note that a rule
+inside `@media` is *not* nested, so `@media … { bottom-nav { … } }`
+elsewhere in that file is fine and needs nothing.
+
+`make css-check` does not catch this (it looks for backticks that end a
+tagged template early). Filed as an issue: the check is the natural
+place for it, being the same shape of trap — a silent, phone-only,
+screenshot-only failure.
+
+## Centring a bar costs the control in the middle of it (measured 2026-08-20)
+
+#23 asks for the transport centred in the bottom bar. The obvious
+implementation — make the outer two grid tracks the same width, so the
+middle is centred by construction — is right, and the first cut of it
+was a regression, because "the same width" was taken to mean *the
+metadata's* width on both sides.
+
+Measured at 800px, with the seek bar's own track:
+
+| layout | seek track | transport column |
+|---|---|---|
+| `320px 1fr auto` (before) | 257 | 407 |
+| both sides `--now-playing-width` | **61** | 179 |
+| both sides `min(--now-playing-width, 25%)` | 246 | 364 |
+
+At 200% text the middle row is worse still: 130 before, **0** with the
+uncapped sides. Centring is free at 1440 and expensive at 800, so a
+change checked only at a comfortable width looks perfect.
+
+The general form: **a symmetric layout reserves space on the side that
+does not need it.** The right-hand group here is ~141px (volume plus
+the queue button) and was being given 320 to keep the arithmetic
+symmetric. Cap the side tracks against the *bar*, not against their
+content, and the middle gets the difference.
+
+The spec that pins this is two assertions, not one, and that split is
+deliberate: an uncapped build is *perfectly centred* and fails only the
+seek-bar width, so a spec asserting centring alone would have passed
+the regression.
+
+## The phone's way into Now Playing was under the artwork (measured 2026-08-20)
+
+`phone-shell.spec.ts`'s "opens the full-screen now playing" failed in CI
+on both engines, three times across two branches that could not have
+caused it, and passed on re-run each time. It was filed as a flake
+(#150). It is not one: **it depends on which track is playing.**
+
+`.expand` — the phone's only route into `<now-playing-view>` — is
+`position: absolute; inset: 0` inside `.cover-art-wrapper`, and
+`.cover-art` is a **later sibling**. Both have `z-index: auto`, so they
+tie on paint order and the later one wins. With an `<img>` that costs
+nothing; with no artwork the placeholder `wa-icon` renders and takes
+every click aimed at the button underneath it.
+
+Measured at 390px with `elementFromPoint` at the button's centre:
+
+| playing track | hit test |
+|---|---|
+| has artwork | `button.expand` |
+| no artwork | **`wa-icon`** |
+| no artwork, with `z-index: 1` | `button.expand` |
+
+So on a phone, the only way into the full-screen player stopped working
+whenever the current song had no cover — and this has nothing to do with
+the fixture: any library has untagged files.
+
+Three things worth keeping.
+
+**"Flaky in CI" was the wrong diagnosis and it cost three cycles.** The
+spec starts the *first* row of the track list, so which track it plays
+is the order the scan inserted rows in — the same root cause as #156,
+one spec over. A test whose subject is a hit test has to *choose* the
+case that breaks it.
+
+**The first two hypotheses were both wrong, and both were plausible.**
+A custom element's upgrade replacing its own contents, and the cover
+preview's `mouseenter` opening a popup under the pointer. Neither
+survived contact with `elementFromPoint`, which took a minute and would
+have saved the other two cycles.
+
+**And the spec that pins it needs the 90-second track**, because a
+2-second one finishes before the assertions run — the trap
+`fixtures.ts` already documents. Note the filter that does *not* work:
+`library.Track.CoverArt` is empty for all 31 fixture rows, so "the
+first track with no cover art" selects nothing in particular. The
+placeholder's presence is asserted instead, which is the property the
+test actually depends on.
+
+## An activity recreation kills the process, deterministically (measured 2026-08-20)
+
+#52's report was "sometimes crashes or restarts when reopened after
+running in the background". Measured on a real device, the *fault* is
+not intermittent at all — only its trigger is.
+
+Device: Light Phone III (TLP301), Android 14 / SDK 34, arm64-v8a,
+WebView **Chrome 113** at 424x439 CSS px. Debug build
+(`app.yellowjacket.dev`), installed beside the released `v0.3.1` with
+`install -r`.
+
+**Conditional on the activity actually being recreated in a live
+process, the process died 8 times out of 8** — 3 by hand, then 5/5 in a
+scripted loop. The runs where it survived were runs where no recreation
+happened (one `Wails bridge initialized` in the log rather than two), so
+they are inconclusive rather than passes; a harness that does not check
+for the second init reports those as green and reads as flakiness.
+After the fix: 5/5 recreations survived, plus 6 background/foreground
+cycles and 3 interleaved recreations on one pid.
+
+The mechanism is three log lines:
+
+```
+12:47:56.159 I/WailsBridge(22956): Wails bridge initialized
+12:48:38.898 I/WailsBridge(22956): Wails bridge initialized   <- same pid
+12:48:39.357 I/ActivityManager: Process app.yellowjacket.dev (pid 22956) has died: fg  TOP
+```
+
+`nativeInit` runs `go mainFunc()` on every activity creation; the second
+`main()` reaches `app.Run()`, which refuses because `a.starting` is
+still true behind Android's `select{}`, and `os.Exit(1)` takes the whole
+process — including the healthy first app — with it.
+
+Four things worth keeping:
+
+- **`has died: fg  TOP` is not a memory kill.** The system does not
+  reclaim the foreground process. This reads as "the OS killed us",
+  which is the wrong hypothesis and the reason the issue sat unverified.
+- **There is no crash record of any kind**: `logcat -b crash` empty, no
+  `AndroidRuntime`, no `libc: Fatal signal`, no tombstone. `os.Exit` is
+  not a crash. The one line that named the fault —
+  `slog.Error("application error", "err", ...)`, carrying
+  `"application is running or a previous run has failed"` — went to
+  `/dev/null`. That is #160.
+- **"Don't keep activities" does not work on this device.**
+  `settings put global always_finish_activities 1` reads back as `1`,
+  `am set-always-finish-activities` does not exist on this build, and
+  the activity was never finished on backgrounding. The report's own
+  suggested lever is a dead end here. What *does* work, deterministically
+  and in one line, is a configuration change the manifest does not
+  declare: `adb shell settings put system font_scale 1.15`
+  (`AndroidManifest.xml` declares `orientation|screenSize|
+  keyboardHidden|uiMode`, so none of those are triggers).
+- **Surviving is only half the property.** The recreated WebView has to
+  still be wired to the running app, which was verified by hooking
+  `window._wails.dispatchWailsEvent` and backgrounding/foregrounding:
+  `["IndexStatusChanged","JobsChanged","JobsChanged",
+  "android:storageAccess"]`. The tempting Java-side fix — making
+  `WailsBridge.initialized` static — passes the pid check and fails
+  this one, because `nativeInit` is also what re-points the JNI
+  reference at the new bridge.
+
+## The Taskfile's device tasks uninstall the released app (2026-08-20)
+
+`android:run:device` builds the **debug** variant
+(`applicationIdSuffix ".dev"`) and then runs
+`adb uninstall {{.APP_ID}}`, where `APP_ID` defaults to
+`app.yellowjacket` — the **release** id. So it deletes the user's
+installed app and its library, installs a different package, and then
+fails to launch the one it removed. `deploy-device` carries the same
+uninstall. Filed as #159; `android-tier.md` had been recommending
+`run:device` as the way onto a device.
+
+This is the hazard that file already names — "The identity is declared
+twice ... **Nothing enforces that they agree**" — reached by a second
+route: the two ids differ not because someone edited one, but because
+the debug buildType suffixes it.
+
+## The uninstall was there to make a bare `install` work (measured 2026-08-20)
+
+Fixing #159 turned up *why* the `adb uninstall` was in all four tasks,
+which the issue does not say and which decides whether it can simply be
+deleted. The line under it was `adb install`, with **no `-r`** — and
+Android refuses an install over an existing package without it. So the
+uninstall was not a deliberate clean-slate step; it was the price of
+the missing flag, paid on every run, and `install -r` removes the
+reason for it rather than merely removing it.
+
+That matters because "should the uninstall go at all" looked like a
+trade — drop it and a signing-certificate change fails with
+`INSTALL_FAILED_UPDATE_INCOMPATIBLE` instead of being handled. It is
+not a trade: nothing else was relying on it. The certificate case is
+reported with the command to run, which is what
+`scripts/android-emulator.sh` already did for `make android-install`,
+so this is one existing judgement applied consistently rather than a
+new one.
+
+## `wails3 task android:run` installs on a phone (measured 2026-08-20)
+
+The emulator tasks (`run`, `deploy-emulator`) used a bare `adb install`
+with no `-s`. adb with exactly one device attached uses that device
+whatever kind it is, so with a phone plugged in and no emulator
+running, the task whose summary reads "in the Android Emulator"
+installed on the phone — and, before #159 was fixed, ran
+`adb uninstall app.yellowjacket` against it first. The reported data
+loss was reachable from the *emulator* task, which is not what the
+issue describes and is worse, because nothing in the name warns you.
+
+Measured after the fix, phone attached and emulator stopped:
+
+```
+$ ./scripts/android-deploy.sh --apk bin/yellowjacket.apk --target emulator
+android-deploy: no emulator target is online.
+    LP3LHMA531900746	device
+    Start one with:  make android-emulator
+```
+
+The general form: **a task that names a target has to say so to adb.**
+The device tasks always filtered on `$1 !~ /^emulator-/`; the emulator
+tasks filtered on nothing at all.
+
+## The package id can be read back, and costs nothing (2026-08-20)
+
+`aapt2 dump packagename <apk>` answers in one word and ~40 ms, from
+`$ANDROID_HOME/build-tools/*/aapt2` (versioned, so resolved not
+pinned); `aapt dump badging` is the fallback for older build-tools and
+is what #159's own measurement used. That is cheap enough to do on
+every deploy, which is what makes "the two ids agree by construction"
+affordable rather than aspirational — the alternative considered was
+giving the debug-flavoured tasks `APP_ID` + `.dev`, which is one line
+and leaves the class of bug alive for the next flavour or suffix.
+
+The guard runs **before** a target is chosen, deliberately: it is a
+question about the artifact, so it can be exercised with nothing
+plugged in, and a build whose id is wrong should be refused whether or
+not there is anything to install it onto. That is what let the negative
+test run safely with the user's phone attached:
+
+```
+$ ./scripts/android-deploy.sh --apk bin/yellowjacket.apk \
+      --target device --expect app.yellowjacket
+android-pkgid: refusing to act on a package this APK does not declare.
+    the APK declares:  app.yellowjacket.dev
+    the task expects:  app.yellowjacket
+rc=2
+```
+
+That is exactly #159's configuration — debug APK, release id, real
+device — refused with no adb call made.
+
+## `make android-emulator`'s boot wait can be satisfied by a phone (2026-08-20)
+
+Noticed while booting the emulator for #159's verification, with a
+phone also attached. `scripts/android-emulator.sh start` reported
+`waiting for boot ok / android 14` about **eight seconds** after
+launching the emulator, which had not appeared in `adb devices` yet —
+`pick_device`'s last resort is "exactly one device online", and at that
+moment the one online device was the phone. So it waited for the
+phone's boot, found it long since booted, and returned. The emulator
+took another ~10 s to come up.
+
+Harmless here (the emulator was up before anything used it) and a
+straightforward race otherwise: `start` should wait for a device that
+is an emulator, not for whatever `pick_device` returns. Filed as #162.

CLAUDE.md

@@ -317,6 +317,60 @@ stacking dialogs. Window state moved off that path entirely, onto a
 window still exists and `OnShutdown` has neither a context nor a
 window.
 
+**An activity is a view onto the process, and `main()` runs once per
+process.** On Android the Wails entry point is `nativeInit`, which
+`MainActivity.onCreate` calls — and it does two things: it re-points the
+native library's global JNI reference at the calling `WailsBridge`, and
+it runs `go mainFunc()`. Android destroys and recreates an activity
+**without restarting the process** (a configuration change the manifest
+does not declare, memory pressure, or every background under "Don't keep
+activities"), so `main()` ran again on a live app. `application.New`
+returns the *existing* app rather than building a second one,
+`app.Run()` then refuses — `a.starting` is still true, because Android's
+`platformRun` is `select{}` and never returns — and the `os.Exit(1)`
+under that error took the **first**, healthy app down with it: its
+database, its queue, and the audio a `mediaPlayback` foreground service
+was holding the process alive to play. `mainStarted` latches it, first
+statement in `main()`.
+
+Four things about it are load-bearing.
+
+**The answer to "restore the session or cold-start" is settled by
+playback, not by preference.** The audio lives in the Go process, so a
+cold start on every activity recreation would stop the music mid-song —
+which is the exact thing the foreground service exists to prevent. The
+activity is a view; the app is the process. The frontend already
+cooperates, because a recreated WebView loads the page fresh and fetches
+its state from a backend that never went away.
+
+**Returning early is not a degraded mode, and that is why the latch is
+in Go rather than in Java.** The obvious fix — making
+`WailsBridge.initialized` `static`, so the second `nativeInit` is
+skipped — keeps the process alive and silently breaks the app, because
+skipping `nativeInit` skips the reference re-point too: Go would keep
+executing JavaScript against the *destroyed* activity's WebView, and the
+app would open, render, and never receive another backend event. The
+latch lets `nativeInit` do its first job and declines only its second.
+
+**`ServiceShutdown` has never run on Android**, and nothing should be
+built on the assumption that it will. `App.Quit()` reaches an
+`androidApp.destroy()` that is an empty method, and `Run()`'s deferred
+`shutdownServices()` cannot fire behind `select{}`. Durability on this
+platform is the persist writers, which submit on every mutation rather
+than at exit — which is also why `MainActivity.onDestroy` no longer
+calls `bridge.shutdown()`: the activity going away is not the app
+shutting down, and there is no callback for the process going away
+because Android simply kills it.
+
+**No tier here can see any of this**, so the guard is split. A source
+sweep (`TestMainClaimsBeforeItDoesAnything`) asserts the latch is the
+*first* statement of `main()` — the failure it exists for is not
+deletion, which is loud, but a line creeping in above it, since a second
+`NewYellowJacketApp` opens the SQLite database again on every
+recreation. The rest is a documented device check in
+`.pi/skills/yellowjacket-dev/references/android-tier.md`, with the
+logcat signature and a one-line way to force a recreation.
+
 `internalServiceMethods` auto-excludes `ServiceStartup`,
 `ServiceShutdown`, `ServiceName` and `ServeHTTP` from bindings, so this
 shape **removed** 12 spurious bindings and the bogus `context` model
@@ -514,6 +568,36 @@ rather than renaming them.
   the autotag apply are registered; anything that is not registered has
   none of that, which is exactly how the three gaps the audit found
   came about.
+
+  **Its rows are shown where the work is started, not on a page of
+  their own.** #27 folded the Jobs destination away, and the shape it
+  folded into is `<job-panel kinds="…">` embedded four times — scans in
+  Settings → Libraries, index and enrichment in Settings → Search
+  Index, downloads under the download clients, the autotag apply in
+  `autotag-view`. One "Background jobs" section in Settings was the
+  obvious reading of the report and is the tab again under another
+  name.
+
+  Four things about it are load-bearing. **Four of the five kinds
+  already had a home** that showed their work — the tier list, the
+  download list, the apply ring — and what none of them had is the
+  *generic* affordances, so the panel carries pause, cancel, Details
+  and the log to each rather than replacing what is there. **The
+  controls are `applyJobControl`**, not a reimplementation, which is
+  what keeps the "you will discard hours of downloading" confirmation
+  alive: it is keyed on `KindIndexBuild` inside the shared handler, and
+  a host drawing its own buttons would drop it silently. **A panel with
+  nothing to say is `hidden`**, host margin included, because an idle
+  panel in four places is four pieces of furniture describing an
+  absence. And **there is no "Clear finished"** in it, because
+  `ClearFinishedJobs` is global — a Clear under Libraries would discard
+  the index build's history too; a finished row dismisses itself.
+
+  The header `job-indicator` is untouched and is still the one view of
+  everything at once, from every page. One consequence worth knowing
+  before writing a spec: a section holding a `job-panel` also holds a
+  `job-details-drawer`, whose own header carries `.header` — so
+  `config-section .header` is ambiguous the moment a job exists.
 - `config` — TOML-based settings. Settings page uses HTMX + templ for server-rendered HTML fragments.
 - `playlist` / `smartplaylist` — Playlist CRUD and rule-based smart playlists.
 - `mediacontrols` — OS media controls behind one `Handler`: MPRIS over
@@ -1032,6 +1116,80 @@ whole way through — so it was green on the broken build. Same trap as
 `layout-overflow.spec.ts` and `page-header`: a spec named for the
 behaviour, measuring the plumbing.
 
+**Which destinations exist is configuration, and hiding one takes away
+the nav item and nothing else.** Eleven sidebar entries is more than
+most libraries need (#25), so each is toggleable from Settings →
+Navigation, Autotag is off until asked for, and Downloads is absent
+until there is a client to download with — a destination for a feature
+that cannot work is worse than none. `navigate` still resolves a hidden
+view, which is not a nicety: detail views navigate into these and the
+launch page is one of them. Nothing needed a special case for the
+highlight either, because the paragraph above moved that onto
+`active-view-store`: the sidebar asks `isActive(id)` per *rendered*
+item, so a hidden view lights nothing exactly as a detail view does.
+
+Five things about it are load-bearing.
+
+**The stored shape is a map keyed by view id, and an absent key means
+that view's own default** (`backend/config.Views`). That is what makes
+this need no migration in either direction, and it is the polarity rule
+`AllowMeteredCatalogDownload` states: the zero value is the intended
+answer. A `HiddenViews []string` cannot express "Autotag off by
+default" at all — its zero value is *hide nothing* — and a struct with
+a boolean per view turns a view that later stops existing into stored
+garbage. Here an unknown key is dropped on load and a view added later
+gets its own default rather than being invisible or forcibly visible.
+It is also what makes #73's `#25 → #27` order safe rather than
+backwards: when Jobs folds into Settings, `jobs = true` in somebody's
+config is a key nothing asks about.
+
+**Two states the user could not get out of are refused, in the config
+and not in the checkbox.** Settings is never hideable and the launch
+page is not hideable while it is the launch page. `config.toml` is
+hand-editable, so a disabled checkbox is the affordance and
+`SetViewVisible` is the rule — an app that can be locked out of its own
+Settings by a typo in TOML is a support problem nobody can debug
+remotely. On *load* the launch page is instead un-hidden rather than
+refused: there is nobody to tell, and the honest reading of "my launch
+page is Autotag" is that this user wants Autotag, not that their launch
+page should be silently reset to something they did not choose.
+
+**Downloads is gated at the nav and not in the config**, on
+`downloadStore.available`, so switching it on in Settings still means
+what it says once a client exists and the tab appears without a restart
+(#37's rule). `available` is false until the providers have loaded,
+which makes the item *appear* on a fresh launch rather than appearing
+and then vanishing.
+
+**The tab bar honours the toggles too, and the reason is local rather
+than a general rule about phones.** `PHONE_COLUMN_IDS` is the precedent
+for "what a phone shows is a different question", and it would apply —
+except that `bottom-nav`'s "More" opens the *same* `<app-sidebar>`,
+which filters, so an unfiltered bar would contradict its own drawer one
+tap away. Which four tabs is still plan 016's committed subset; this
+only removes from it, and "More" is never filtered because it is how
+everything else stays reachable.
+
+**A retired destination is the one shape this does not make free.** An
+absent visibility key takes its default and an unknown one is dropped,
+but `DefaultPage` is a *value*: a launch page naming a view that no
+longer exists fails validation, and on the load path that means the app
+refuses to start for whoever had it selected. `RetiredViews` is that
+list, and `ApplyDefaults` treats a retired name as a zero value while
+an unknown-but-not-retired one still errors — a typo is worth being
+told about. #27 retiring `jobs` is its first entry.
+
+**The list of destinations is `services/view-meta.ts`**, on
+`shortcut-meta.ts`'s pattern, because #25 gave it a second reader:
+Settings renders a toggle per view and needs the same labels in the
+same order. Which views exist and what an unconfigured install shows is
+Go's (`backend/config.Views`, which `DefaultPage`'s validation reads
+too, so the launchable set is not a second list); how they are *drawn*
+is the frontend's, beside the rest of the icon vocabulary. The binding
+returns the **resolved** map for every view, so the frontend holds no
+copy of the defaults — which would be the copy that shipped in the
+binary rather than the one being edited.
+
 **A primary view is cached, not unmounted.** `index.ts` keeps every
 primary view in the DOM and toggles a `.view-hidden` class, because that
 is what preserves `scrollTop` across navigation — so
@@ -1416,6 +1574,102 @@ three, *no action is ever unreachable at any supported size*. The bands
 themselves already existed; what was new is that they are a promise and
 that the queue panel is inside it.
 
+**The top bar decides what it can afford, and what it gives up is never
+an action.** Its five children do not fit at the bottom of the Compact
+band: the bar was 611px inside a 600px viewport idle and **862px while
+a scan ran**, because `job-indicator` is `hidden` when idle and 235px
+wide showing a real library's scan title (#143). So `services/
+top-bar-fit.ts` is `page-header`'s treatment one bar up — a
+ResizeObserver, every pass starting from all-visible, hiding the
+lowest-priority child until it fits.
+
+Five things about it are load-bearing.
+
+**It is measured rather than breakpointed for a reason specific to this
+bar**: three of its five children are as wide as their *content* — the
+library filter is a `<select>` sized by the longest library name, the
+indicator by the running job's title, the search box by its view-scoped
+placeholder — so any width picked is right for one library, one job and
+one view. Swept with a long-titled scan staged, the bar overflowed at
+**every** width from 600 to 899 *and* at 900 where `nav-history`
+appears, while 899 fits; a breakpoint fixing "600 to 610" would have
+fixed whichever case happened to be idle when it was measured.
+
+**What yields is decided by the promise above, which rules out the two
+cheapest answers.** Hiding the library filter takes away an action —
+`library-filter` is the only control in the app that calls
+`setSelectedLibrary` — so it trades this promise for the same promise
+(#148 is the phone already doing that). Collapsing the search box to an
+icon is what #57 wants and #57 is blocked behind #62, so building it
+here is building it without the thing that blocks it. The two that
+yield are the two that are **not** actions: the wordmark, which the
+window's own title bar repeats and which #48 wants down to "YJ" at
+every width anyway, and then the job indicator's *label*, leaving the
+ring — which is not a new judgement, since the component already drops
+it below 600px and its `sr-only` live region is what announces the
+state either way.
+
+**The wordmark yields its width, not its existence.** The collapsed
+rule is visually-hidden rather than `display: none`, because that `h1`
+is the document's top-level heading as well as the brand.
+
+**"Fits" is the children against the content box, and `scrollWidth`
+cannot express it.** `scrollWidth` counts a box's left padding and not
+its right, so with 2em gutters it under-reports by 32px: the first fix
+read `700/700` — a perfect fit — with the indicator sitting in the
+whole right gutter. Same family as #69's title trap, and found only
+because `top-bar-fit.spec.ts` measures **per child**, which is what
+`layout-overflow.spec.ts` cannot do and why that spec was green
+throughout the defect.
+
+And **the bar does not resize when a job starts**, which is the case the
+whole thing is for — a ResizeObserver on the header alone never fires,
+so every element child is observed too.
+
+**The bottom bar is three columns whose outer two are the same width,
+and that is what "centred" means.** It was `320px 1fr auto`, so the
+transport sat in the middle of the space the metadata and the queue
+button did not use — its centre was ~140px right of the window's at
+every size (#23). The outer tracks are now the same expression, so the
+middle one is centred by construction rather than by arithmetic that
+has to be redone whenever a control joins the bar.
+
+Four things about it are load-bearing.
+
+**The side width is the metadata's, capped at a quarter of the bar**,
+and the cap is not tidiness — it was measured as a regression first.
+Reserving the full `--now-playing-width` on *both* sides costs the
+transport twice: at 800px the outer pair wanted 640 of 800 and the seek
+bar's track fell from **257px to 61px**, and to 0 at 200% text. The
+control you drag was being squeezed to centre the buttons above it.
+With the cap it is 246px at 800, which is parity with the uncentred
+layout.
+
+**The cap is a `min()` rather than a breakpoint** because
+`--now-playing-width` is *user state* — the metadata panel has a drag
+handle — and the same reasoning the queue panel's overlay mode uses
+applies: a rule that assumed the default 320 would be wrong by whatever
+the user dragged. Tying both sides to that variable is also what keeps
+the handle meaningful; a plain `1fr … 1fr` would centre the transport
+just as well and silently make dragging a no-op.
+
+**The volume moved out of `audio-player` and into the bar** (#42),
+because the transport column has to hold the transport and nothing
+else or "centred" means centred with a slider bolted to one side. It
+lives in `.bar-end` with the queue button — one cell, not two columns,
+since the centring compares *columns* and a separate volume track would
+make the outer pair unequal by whatever the slider measures.
+
+And **the slider is inline by default, with the popup as a setting**
+whose stored flag names the *popup*: `backend/config`'s polarity rule,
+where the zero value has to be the intended answer, so an existing
+`config.toml` with no key gets the new default without a migration.
+Inline, the icon becomes the mute toggle and is named after that action
+rather than after the state, because with the slider beside it there is
+nothing left to disclose. It stands down below 600px whatever the
+setting says — that is about the platform rather than preference, and
+is why `mediacontrols`' Android handler implements no volume callback.
+
 **900 is the worst desktop width, not the 800×600 minimum.** The
 sidebar collapses to icons *below* 900, so the main panel is 843px at
 899 and 700px at 900 — the narrowest content area any desktop width

backend/config/config.go

@@ -544,7 +544,7 @@ func (c *Config) SetDefaultPage(page string) error {
 		c.General.ApplyDefaults()
 	}
 
-	c.General.DefaultPage = DefaultPage(page)
+	c.General.DefaultPage = View(page)
 
 	if err := c.General.Validate(); err != nil {
 		return fmt.Errorf(
@@ -666,6 +666,124 @@ func (c *Config) SetAllowMeteredCatalogDownload(allow bool) error {
 	return nil
 }
 
+// GetPopupVolume reports whether the bottom bar's volume control is a
+// click-to-open popup rather than an inline slider (#42).
+func (c *Config) GetPopupVolume() bool {
+	if c.General == nil {
+		return false
+	}
+
+	return c.General.PopupVolume
+}
+
+// SetPopupVolume saves the volume control's presentation.
+//
+// Nothing to validate: both values are legal at every width, and the
+// frontend additionally stands the inline slider down below the phone
+// breakpoint whatever this says, because that is about room rather than
+// about preference.
+func (c *Config) SetPopupVolume(popup bool) error {
+	if c.General == nil {
+		c.General = &GeneralConfig{}
+		c.General.ApplyDefaults()
+	}
+
+	c.General.PopupVolume = popup
+
+	if err := c.Save(); err != nil {
+		return fmt.Errorf(
+			"could not save config: %w", err,
+		)
+	}
+
+	events.Emit(
+		c.ctx,
+		events.GeneralConfigChanged,
+		map[string]any{
+			"PopupVolume": popup,
+		},
+	)
+
+	c.logger.Info("volume control presentation updated", "popup", popup)
+
+	return nil
+}
+
+// GetViewVisibility reports which primary views the sidebar should
+// show, answered for every known view rather than only the ones the
+// config mentions -- so the frontend filters on a value and never has
+// to hold a second copy of the defaults.
+func (c *Config) GetViewVisibility() map[string]bool {
+	if c.General == nil {
+		general := &GeneralConfig{}
+		general.ApplyDefaults()
+
+		return general.ResolvedViewVisibility()
+	}
+
+	return c.General.ResolvedViewVisibility()
+}
+
+// SetViewVisible shows or hides one primary view.
+//
+// Two refusals, both about a state the user cannot get out of from the
+// UI they would be left with: Settings is never hideable, and the
+// launch page is never hideable while it is the launch page (change it
+// first). Hiding a view does not make it unreachable -- `navigate`
+// still resolves it, which detail views depend on -- it only takes the
+// nav item away.
+func (c *Config) SetViewVisible(view string, visible bool) error {
+	spec, known := LookupView(view)
+	if !known {
+		return fmt.Errorf("%w: %q", errUnknownView, view)
+	}
+
+	if c.General == nil {
+		c.General = &GeneralConfig{}
+		c.General.ApplyDefaults()
+	}
+
+	if !visible {
+		if !spec.Hideable {
+			return fmt.Errorf("%w: %q", errViewNotHideable, view)
+		}
+
+		if spec.ID == c.General.DefaultPage {
+			return fmt.Errorf("%w: %q", errViewIsLaunchPage, view)
+		}
+	}
+
+	if c.General.ViewVisibility == nil {
+		c.General.ViewVisibility = make(map[string]bool, len(Views))
+	}
+
+	c.General.ViewVisibility[view] = visible
+
+	if err := c.General.Validate(); err != nil {
+		return fmt.Errorf("invalid view visibility: %w", err)
+	}
+
+	if err := c.Save(); err != nil {
+		return fmt.Errorf("could not save config: %w", err)
+	}
+
+	events.Emit(
+		c.ctx,
+		events.GeneralConfigChanged,
+		map[string]any{
+			"ViewVisibility": c.General.ResolvedViewVisibility(),
+		},
+	)
+
+	c.logger.Info(
+		"view visibility updated",
+		"view", view,
+		"visible", visible,
+	)
+
+	return nil
+}
+
 // GetTrackListColumns returns the configured track-list columns.
 func (c *Config) GetTrackListColumns() []tracklist.Column {
 	if c.TrackList == nil {

backend/config/emit_test.go

@@ -188,3 +188,43 @@ func TestEmit_FavoritesChangeCarriesFullConfig(t *testing.T) {
 		}
 	}
 }
+
+// TestEmit_PopupVolumeRoundTripsAndDefaultsToInline pins both halves of
+// #42's storage decision.
+//
+// The **default** is the load-bearing one: inline is what a fresh
+// install and an existing `config.toml` with no such key must both
+// produce, which is why the field names the popup rather than the
+// inline slider. A flag spelled the other way round would default to
+// false, hand every existing install the popup this issue exists to
+// stop being the only option, and need a migration to say otherwise.
+func TestEmit_PopupVolumeRoundTripsAndDefaultsToInline(t *testing.T) {
+	t.Parallel()
+
+	conf, rec := setupRecordedConfig(t)
+
+	if conf.GetPopupVolume() {
+		t.Error("a config with no PopupVolume key wants the popup, want inline")
+	}
+
+	if err := conf.SetPopupVolume(true); err != nil {
+		t.Fatalf("SetPopupVolume: %v", err)
+	}
+
+	if !conf.GetPopupVolume() {
+		t.Error("GetPopupVolume = false after setting it true")
+	}
+
+	data := payloadMap(t, rec, events.GeneralConfigChanged)
+	if data["PopupVolume"] != true {
+		t.Errorf("PopupVolume = %v, want true", data["PopupVolume"])
+	}
+
+	if err := conf.SetPopupVolume(false); err != nil {
+		t.Fatalf("SetPopupVolume(false): %v", err)
+	}
+
+	if conf.GetPopupVolume() {
+		t.Error("GetPopupVolume = true after setting it false")
+	}
+}

backend/config/general.go

@@ -5,27 +5,13 @@ import (
 	"fmt"
 )
 
-// DefaultPage identifies which view the app opens to on launch.
-type DefaultPage string
-
-// Valid DefaultPage values, matching the frontend's top-level route ids.
-const (
-	DefaultPageHome      DefaultPage = "home"
-	DefaultPageTracks    DefaultPage = "tracks"
-	DefaultPageAlbums    DefaultPage = "albums"
-	DefaultPageArtists   DefaultPage = "artists"
-	DefaultPageGenres    DefaultPage = "genres"
-	DefaultPagePlaylists DefaultPage = "playlists"
-	DefaultPageExplore   DefaultPage = "explore"
-	DefaultPageDownloads DefaultPage = "downloads"
-	DefaultPageAutotag   DefaultPage = "autotag"
-	DefaultPageJobs      DefaultPage = "jobs"
-)
-
 // DefaultDefaultPage is the launch page for a fresh install.
-const DefaultDefaultPage = DefaultPageHome
+const DefaultDefaultPage = ViewHome
 
-var errUnknownDefaultPage = errors.New("unknown default page")
+var (
+	errUnknownDefaultPage = errors.New("unknown default page")
+	errViewCannotLaunch   = errors.New("view cannot be the launch page")
+)
 
 // QueueFallback identifies what plays, if anything, once the queue
 // runs out with nothing left to auto-advance to.
@@ -46,18 +32,52 @@ var errUnknownQueueFallback = errors.New("unknown queue fallback")
 // GeneralConfig holds general application preferences that don't
 // belong to a more specific subsystem.
 type GeneralConfig struct {
-	DefaultPage   DefaultPage   `toml:"DefaultPage"`
+	DefaultPage   View          `toml:"DefaultPage"`
 	QueueFallback QueueFallback `toml:"QueueFallback"`
+	// ViewVisibility says which sidebar destinations are shown, keyed by
+	// view id.
+	//
+	// **An absent key means that view's own default** (`Views`), and that
+	// is the whole reason this is a map rather than a `HiddenViews
+	// []string` or a struct of booleans. A list's zero value is "hide
+	// nothing", which cannot express Autotag being off by default without
+	// a migration; a struct field for a view that later stops existing is
+	// stored garbage somebody has to deprecate. Here a view added later
+	// gets its own default rather than being invisible or forcibly
+	// visible, an unknown key is dropped on load, and no install needs
+	// migrating in either direction. Same polarity rule as
+	// AllowMeteredCatalogDownload: the zero value is the intended answer.
+	ViewVisibility map[string]bool `toml:"ViewVisibility"`
 	// AllowMeteredCatalogDownload permits the ~0.6 GB Explore catalog to
 	// be fetched on a connection the platform calls cellular. It defaults
 	// to false, which is the whole point: the zero value is the safe one,
 	// so an existing config with no such key refuses by default rather
 	// than needing a migration to become careful.
 	AllowMeteredCatalogDownload bool `toml:"AllowMeteredCatalogDownload"`
+	// PopupVolume draws the bottom bar's volume as a click-to-open popup
+	// instead of a slider that is always there (#42).
+	//
+	// The polarity is the rule this file already states twice: **the
+	// zero value is the intended answer**. Inline is the new default, so
+	// the flag has to name the *other* choice — an `InlineVolume bool`
+	// would default to false and give every existing install the popup
+	// this issue exists to stop being the only option, and would need a
+	// migration to say otherwise.
+	PopupVolume bool `toml:"PopupVolume"`
 }
 
 // ApplyDefaults fills zero-value fields with sensible defaults.
+//
+// A launch page naming a *retired* view is treated as a zero value
+// rather than as an error, because the alternative is an app that will
+// not start for anyone who had that page selected when it was removed.
+// An unknown-but-not-retired name still fails Validate: that is a typo,
+// and telling someone about it is the useful answer.
 func (c *GeneralConfig) ApplyDefaults() {
+	if _, retired := RetiredViews[c.DefaultPage]; retired {
+		c.DefaultPage = ""
+	}
+
 	if c.DefaultPage == "" {
 		c.DefaultPage = DefaultDefaultPage
 	}
@@ -71,15 +91,17 @@ func (c *GeneralConfig) ApplyDefaults() {
 func (c *GeneralConfig) Validate() error {
 	c.ApplyDefaults()
 
-	switch c.DefaultPage {
-	case DefaultPageHome, DefaultPageTracks, DefaultPageAlbums, DefaultPageArtists,
-		DefaultPageGenres, DefaultPagePlaylists, DefaultPageExplore, DefaultPageDownloads,
-		DefaultPageAutotag, DefaultPageJobs:
-		// Valid.
-	default:
+	spec, known := LookupView(string(c.DefaultPage))
+	if !known {
 		return fmt.Errorf("%w: %q", errUnknownDefaultPage, c.DefaultPage)
 	}
 
+	if !spec.CanLaunch {
+		return fmt.Errorf("%w: %q", errViewCannotLaunch, c.DefaultPage)
+	}
+
+	c.normalizeViewVisibility()
+
 	switch c.QueueFallback {
 	case QueueFallbackStop, QueueFallbackFavorites, QueueFallbackDynamicMix:
 		// Valid.
@@ -89,3 +111,51 @@ func (c *GeneralConfig) Validate() error {
 
 	return nil
 }
+
+// normalizeViewVisibility drops what the stored map may not say, and
+// repairs the one invariant the shell depends on.
+//
+// Three things are dropped or forced, and all three are reachable only
+// from a hand-edited config or from a version that knew different
+// views: an unknown id (a view removed since, e.g. when #27 folds Jobs
+// into Settings) says nothing to anybody; a view that is not Hideable
+// cannot be false; and **the launch page is always visible**, because
+// otherwise an install lands on a page with no nav item pointing at it.
+//
+// That last one is a *repair* here and an *error* at the setter
+// (SetViewVisible), deliberately. On load there is nobody to tell and
+// the honest reading of "my launch page is Autotag" is that this user
+// wants Autotag, so it is un-hidden rather than the launch page being
+// silently reset to something they did not choose. At the setter the
+// user is right there and can act, so it refuses and says why.
+func (c *GeneralConfig) normalizeViewVisibility() {
+	for id := range c.ViewVisibility {
+		spec, known := LookupView(id)
+		if !known || !spec.Hideable {
+			delete(c.ViewVisibility, id)
+		}
+	}
+
+	if visible, ok := c.ViewVisibility[string(c.DefaultPage)]; ok && !visible {
+		c.ViewVisibility[string(c.DefaultPage)] = true
+	}
+}
+
+// ResolvedViewVisibility answers for every known view, so no caller has
+// to know the defaults -- the frontend included, which is why the
+// binding returns this rather than the stored map.
+func (c *GeneralConfig) ResolvedViewVisibility() map[string]bool {
+	resolved := make(map[string]bool, len(Views))
+
+	for _, v := range Views {
+		visible := v.VisibleByDefault
+
+		if stored, ok := c.ViewVisibility[string(v.ID)]; ok && v.Hideable {
+			visible = stored
+		}
+
+		resolved[string(v.ID)] = visible
+	}
+
+	return resolved
+}

backend/config/views.go

@@ -0,0 +1,103 @@
+package config
+
+import "errors"
+
+var (
+	errUnknownView      = errors.New("unknown view")
+	errViewNotHideable  = errors.New("view cannot be hidden")
+	errViewIsLaunchPage = errors.New("view is the launch page")
+)
+
+// View identifies one of the shell's primary destinations -- the
+// things the sidebar lists and `index.ts` knows as `VIEW_TAGS`.
+type View string
+
+// The primary views, in no particular order: the sidebar owns the order
+// it draws them in, because that is presentation.
+const (
+	ViewHome      View = "home"
+	ViewPlaylists View = "playlists"
+	ViewArtists   View = "artists"
+	ViewGenres    View = "genres"
+	ViewAlbums    View = "albums"
+	ViewTracks    View = "tracks"
+	ViewExplore   View = "explore"
+	ViewDownloads View = "downloads"
+	ViewAutotag   View = "autotag"
+	ViewSettings  View = "settings"
+)
+
+// RetiredViews are destinations that used to exist and no longer do.
+//
+// A *visibility* entry for a removed view needs no such list: it is a
+// key in a map, and an unknown key is dropped on load. A `DefaultPage`
+// is a **value**, and an unknown one fails validation -- which on the
+// load path means the app refuses to start rather than a setting being
+// ignored. So the one shape that cannot be retired for free is named
+// here and reset to the default instead.
+//
+// `jobs` was folded into Settings by #27: library scans under
+// Libraries, index work under Search Index, downloads under the
+// download clients, and the autotag apply into the Autotag view.
+var RetiredViews = map[View]struct{}{
+	"jobs": {},
+}
+
+// ViewSpec is what the backend knows about a destination. The label and
+// the icon are deliberately absent: those are presentation, they live
+// beside the rest of the app's icon vocabulary in
+// `frontend/src/utils/icon-language.ts`, and a Go copy of them would be
+// a second thing to keep in step for nothing.
+type ViewSpec struct {
+	// ID is the view name the frontend navigates by.
+	ID View
+	// VisibleByDefault is what an install gets when the config says
+	// nothing about this view -- which is every install until somebody
+	// changes it, and every view added after this one shipped.
+	VisibleByDefault bool
+	// Hideable is false for Settings alone. It is a property of the
+	// view rather than a check in the setter because `config.toml` is
+	// hand-editable, and an app that can be locked out of its own
+	// Settings by a typo is a support problem nobody can debug
+	// remotely.
+	Hideable bool
+	// CanLaunch reports whether the view may be the launch page.
+	// Settings is the only one that may not, which is the shape the
+	// DefaultPage enum already had.
+	CanLaunch bool
+}
+
+// Views is the one list of primary destinations, in the order Settings
+// offers them.
+//
+// It is the single source for three things that used to be written down
+// separately: which views exist, which of them may be the launch page
+// (`DefaultPage`'s validation reads it), and what an unconfigured
+// install shows.
+//
+// Autotag is the one view hidden by default: it rewrites tags on disk,
+// which is not what most libraries want on day one, and #25 asks for it
+// to be turned on deliberately.
+var Views = []ViewSpec{
+	{ID: ViewHome, VisibleByDefault: true, Hideable: true, CanLaunch: true},
+	{ID: ViewPlaylists, VisibleByDefault: true, Hideable: true, CanLaunch: true},
+	{ID: ViewArtists, VisibleByDefault: true, Hideable: true, CanLaunch: true},
+	{ID: ViewGenres, VisibleByDefault: true, Hideable: true, CanLaunch: true},
+	{ID: ViewAlbums, VisibleByDefault: true, Hideable: true, CanLaunch: true},
+	{ID: ViewTracks, VisibleByDefault: true, Hideable: true, CanLaunch: true},
+	{ID: ViewExplore, VisibleByDefault: true, Hideable: true, CanLaunch: true},
+	{ID: ViewDownloads, VisibleByDefault: true, Hideable: true, CanLaunch: true},
+	{ID: ViewAutotag, VisibleByDefault: false, Hideable: true, CanLaunch: true},
+	{ID: ViewSettings, VisibleByDefault: true, Hideable: false, CanLaunch: false},
+}
+
+// LookupView returns the spec for a view id.
+func LookupView(id string) (ViewSpec, bool) {
+	for _, v := range Views {
+		if string(v.ID) == id {
+			return v, true
+		}
+	}
+
+	return ViewSpec{}, false
+}

backend/config/views_test.go

@@ -0,0 +1,307 @@
+package config
+
+import (
+	"errors"
+	"log/slog"
+	"path/filepath"
+	"testing"
+)
+
+// newViewTestConfig builds a Config backed by a temp file, which is all
+// SetViewVisible needs: it saves and emits, and the emit is a no-op
+// without a running app.
+func newViewTestConfig(t *testing.T) *Config {
+	t.Helper()
+
+	c := &Config{
+		logger:   slog.Default(),
+		filePath: filepath.Join(t.TempDir(), "config.toml"),
+	}
+
+	// Load a file that is not there: that is what marks the config
+	// loaded, without which Save refuses on the *second* write.
+	if err := c.Load(); err != nil {
+		t.Fatalf("Load() error: %v", err)
+	}
+
+	return c
+}
+
+// A view the config says nothing about takes its own default, which is
+// what makes this need no migration in either direction: an existing
+// install gets Autotag hidden without a key, and a view added later
+// gets its own answer rather than the list's.
+func TestViewVisibilityDefaults(t *testing.T) {
+	t.Parallel()
+
+	general := &GeneralConfig{}
+	general.ApplyDefaults()
+
+	resolved := general.ResolvedViewVisibility()
+
+	if len(resolved) != len(Views) {
+		t.Fatalf("resolved %d views, want %d", len(resolved), len(Views))
+	}
+
+	if resolved[string(ViewAutotag)] {
+		t.Error("autotag should be hidden by default")
+	}
+
+	for _, v := range Views {
+		if v.ID == ViewAutotag {
+			continue
+		}
+
+		if !resolved[string(v.ID)] {
+			t.Errorf("%s should be visible by default", v.ID)
+		}
+	}
+}
+
+// A stored answer wins over the default, in both directions -- turning
+// Autotag on is the whole user-facing point.
+func TestViewVisibilityStoredWins(t *testing.T) {
+	t.Parallel()
+
+	general := &GeneralConfig{
+		ViewVisibility: map[string]bool{
+			string(ViewAutotag): true,
+			string(ViewExplore): false,
+		},
+	}
+	general.ApplyDefaults()
+
+	resolved := general.ResolvedViewVisibility()
+
+	if !resolved[string(ViewAutotag)] {
+		t.Error("autotag was switched on and should be visible")
+	}
+
+	if resolved[string(ViewExplore)] {
+		t.Error("explore was switched off and should be hidden")
+	}
+}
+
+// A key for a view that no longer exists is discarded rather than
+// migrated. This is the property the #25-before-#27 ordering rests on:
+// when Jobs folds into Settings, `jobs = true` in somebody's config is
+// a key nothing asks about, not a cleanup task.
+func TestValidateDropsUnknownAndUnhideableViews(t *testing.T) {
+	t.Parallel()
+
+	general := &GeneralConfig{
+		ViewVisibility: map[string]bool{
+			"a-view-that-was-removed": true,
+			string(ViewSettings):      false,
+			string(ViewAutotag):       true,
+		},
+	}
+
+	if err := general.Validate(); err != nil {
+		t.Fatalf("Validate() error: %v", err)
+	}
+
+	if _, ok := general.ViewVisibility["a-view-that-was-removed"]; ok {
+		t.Error("an unknown view id should be dropped on load")
+	}
+
+	if _, ok := general.ViewVisibility[string(ViewSettings)]; ok {
+		t.Error("settings is not hideable and should not be stored")
+	}
+
+	if !general.ResolvedViewVisibility()[string(ViewSettings)] {
+		t.Error("settings must resolve visible whatever the file said")
+	}
+}
+
+// On load there is nobody to tell, so a launch page hidden by a
+// hand-edited file is un-hidden rather than the launch page being
+// reset to something the user did not choose.
+func TestValidateRevealsAHiddenLaunchPage(t *testing.T) {
+	t.Parallel()
+
+	general := &GeneralConfig{
+		DefaultPage: ViewAutotag,
+		ViewVisibility: map[string]bool{
+			string(ViewAutotag): false,
+		},
+	}
+
+	if err := general.Validate(); err != nil {
+		t.Fatalf("Validate() error: %v", err)
+	}
+
+	if !general.ResolvedViewVisibility()[string(ViewAutotag)] {
+		t.Error("the launch page must be visible")
+	}
+}
+
+// A launch page naming a view that no longer exists resets to the
+// default instead of failing validation, which on the load path would
+// mean the app refusing to start for whoever had it selected.
+//
+// This is the one shape #25's storage decision does *not* make free: a
+// visibility entry is a key and an unknown key is dropped, but a launch
+// page is a value.
+func TestARetiredLaunchPageFallsBackToTheDefault(t *testing.T) {
+	t.Parallel()
+
+	general := &GeneralConfig{DefaultPage: "jobs"}
+
+	if err := general.Validate(); err != nil {
+		t.Fatalf("Validate() error: %v", err)
+	}
+
+	if general.DefaultPage != DefaultDefaultPage {
+		t.Errorf("DefaultPage = %q, want %q", general.DefaultPage, DefaultDefaultPage)
+	}
+}
+
+// A name that is merely wrong is still an error: that is a typo, and
+// saying so is more useful than ignoring it.
+func TestAnUnknownLaunchPageIsStillAnError(t *testing.T) {
+	t.Parallel()
+
+	general := &GeneralConfig{DefaultPage: "nonsense"}
+
+	if err := general.Validate(); !errors.Is(err, errUnknownDefaultPage) {
+		t.Fatalf("Validate() error = %v, want errUnknownDefaultPage", err)
+	}
+}
+
+// A retired view is not a view, so nothing offers it and nothing
+// resolves it -- the visibility map included.
+func TestARetiredViewIsGone(t *testing.T) {
+	t.Parallel()
+
+	for id := range RetiredViews {
+		if _, ok := LookupView(string(id)); ok {
+			t.Errorf("%s is retired but still in Views", id)
+		}
+
+		general := &GeneralConfig{}
+		general.ApplyDefaults()
+
+		if _, ok := general.ResolvedViewVisibility()[string(id)]; ok {
+			t.Errorf("%s is retired but still resolves a visibility", id)
+		}
+	}
+}
+
+// Settings may not be the launch page, which is the shape the old
+// DefaultPage enum had and is now read off the same table.
+func TestValidateRejectsAnUnlaunchablePage(t *testing.T) {
+	t.Parallel()
+
+	general := &GeneralConfig{DefaultPage: ViewSettings}
+
+	err := general.Validate()
+	if !errors.Is(err, errViewCannotLaunch) {
+		t.Fatalf("Validate() error = %v, want errViewCannotLaunch", err)
+	}
+}
+
+// At the setter the user is present and can act, so the two states
+// they could not get out of are refused rather than repaired.
+func TestSetViewVisibleRefusals(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name    string
+		view    string
+		visible bool
+		want    error
+	}{
+		{"settings is never hideable", string(ViewSettings), false, errViewNotHideable},
+		{"the launch page is not hideable", string(ViewHome), false, errViewIsLaunchPage},
+		{"an unknown view is not a setting", "nonsense", false, errUnknownView},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			c := newViewTestConfig(t)
+
+			err := c.SetViewVisible(tt.view, tt.visible)
+			if !errors.Is(err, tt.want) {
+				t.Fatalf("SetViewVisible() error = %v, want %v", err, tt.want)
+			}
+		})
+	}
+}
+
+// Showing a view is never refused, including Settings and the launch
+// page -- there is no state to be stuck in.
+func TestSetViewVisibleShowsAnything(t *testing.T) {
+	t.Parallel()
+
+	c := newViewTestConfig(t)
+
+	for _, v := range Views {
+		if err := c.SetViewVisible(string(v.ID), true); err != nil {
+			t.Fatalf("SetViewVisible(%q, true) error: %v", v.ID, err)
+		}
+	}
+
+	if !c.GetViewVisibility()[string(ViewAutotag)] {
+		t.Error("autotag was switched on and should be visible")
+	}
+}
+
+// The stored map survives a save/load round trip, which is what a
+// map-valued TOML key is worth checking for.
+func TestViewVisibilityRoundTrips(t *testing.T) {
+	t.Parallel()
+
+	path := filepath.Join(t.TempDir(), "config.toml")
+
+	original := &Config{logger: slog.Default(), filePath: path}
+	if err := original.Load(); err != nil {
+		t.Fatalf("Load() error: %v", err)
+	}
+
+	if err := original.SetViewVisible(string(ViewAutotag), true); err != nil {
+		t.Fatalf("SetViewVisible() error: %v", err)
+	}
+
+	if err := original.SetViewVisible(string(ViewExplore), false); err != nil {
+		t.Fatalf("SetViewVisible() error: %v", err)
+	}
+
+	loaded := &Config{logger: slog.Default(), filePath: path}
+	if err := loaded.Load(); err != nil {
+		t.Fatalf("Load() error: %v", err)
+	}
+
+	resolved := loaded.GetViewVisibility()
+
+	if !resolved[string(ViewAutotag)] {
+		t.Error("autotag should have loaded as visible")
+	}
+
+	if resolved[string(ViewExplore)] {
+		t.Error("explore should have loaded as hidden")
+	}
+}
+
+// Every view the shell can launch into is a view the sidebar can show,
+// or an install could land on a page with no nav item and no setting
+// pointing at it.
+func TestEveryLaunchableViewIsAView(t *testing.T) {
+	t.Parallel()
+
+	for _, v := range Views {
+		if !v.CanLaunch {
+			continue
+		}
+
+		if !v.Hideable {
+			continue
+		}
+
+		if _, ok := LookupView(string(v.ID)); !ok {
+			t.Errorf("%s is launchable but not a known view", v.ID)
+		}
+	}
+}

build/android/Taskfile.yml

@@ -4,18 +4,28 @@ includes:
   common: ../Taskfile.yml
 
 vars:
-  # The *installed* package name, which every adb-driven task below uses
-  # to uninstall, launch and filter. It must agree with `applicationId`
-  # in app/build.gradle, and nothing enforces that.
+  # APP_ID is an *assertion*, not a setting, and it has no default.
   #
-  # ANDROID.md says to set this in build/config.yml. That does not work
-  # in beta.8, checked both ways: `wails3 task` builds its var set from
-  # CLI KEY=VALUE arguments and the Taskfile tree only -- nothing reads
-  # config.yml -- and even when set it feeds only these adb commands,
-  # never Gradle. So the identity is declared twice, here and in
-  # build.gradle, and a change to one alone means the official run and
-  # deploy tasks address a package that is not installed.
-  APP_ID: '{{.APP_ID | default "app.yellowjacket"}}'
+  # It used to be the id every adb-driven task below uninstalled,
+  # launched and filtered, defaulting to "app.yellowjacket". It could
+  # never have been a setting: `wails3 task` builds its var set from CLI
+  # KEY=VALUE arguments and the Taskfile tree only -- nothing reads
+  # build/config.yml, contrary to ANDROID.md, checked with --dry -- and
+  # even when set it fed only the adb commands, never Gradle. So the
+  # identity was declared twice, here and as `applicationId` in
+  # app/build.gradle, with nothing enforcing that they agree.
+  #
+  # They did not agree. The debug buildType carries
+  # `applicationIdSuffix ".dev"`, so the tasks that assemble a debug APK
+  # addressed the *release* id -- on a device, the user's installed app
+  # and their library (#159).
+  #
+  # The id is now read back from the built APK by scripts/android-
+  # pkgid.sh, so the thing installed and the thing launched agree by
+  # construction. Passing APP_ID= says "this build had better declare
+  # that id", and the deploy refuses before touching anything if it does
+  # not -- which is the check that would have caught #159 statically.
+  APP_ID: '{{.APP_ID | default ""}}'
   MIN_SDK: '21'
   TARGET_SDK: '35'
   # The emulator runs the host architecture; physical devices are arm64
@@ -372,9 +382,7 @@ tasks:
           ARCH: '{{.ARCH | default .HOST_ARCH}}'
     cmds:
       - task: ensure-emulator
-      - '"{{.ADB}}" uninstall {{.APP_ID}} 2>/dev/null || true'
-      - '"{{.ADB}}" install "{{.BIN_DIR}}/{{.APP_NAME}}.apk"'
-      - '"{{.ADB}}" shell am start -n {{.APP_ID}}/com.wails.app.MainActivity'
+      - './scripts/android-deploy.sh --apk "{{.BIN_DIR}}/{{.APP_NAME}}.apk" --target emulator{{if .APP_ID}} --expect "{{.APP_ID}}"{{end}}'
 
   run:
     summary: Build, install and launch a debug build in the Android Emulator
@@ -383,9 +391,7 @@ tasks:
       - task: build
     cmds:
       - task: assemble:apk
-      - '"{{.ADB}}" uninstall {{.APP_ID}} 2>/dev/null || true'
-      - '"{{.ADB}}" install "{{.BIN_DIR}}/{{.APP_NAME}}.apk"'
-      - '"{{.ADB}}" shell am start -n {{.APP_ID}}/com.wails.app.MainActivity'
+      - './scripts/android-deploy.sh --apk "{{.BIN_DIR}}/{{.APP_NAME}}.apk" --target emulator{{if .APP_ID}} --expect "{{.APP_ID}}"{{end}}'
 
   device:list:
     summary: Lists connected Android devices and emulators (serials)
@@ -400,25 +406,7 @@ tasks:
           ARCH: arm64
     cmds:
       - task: assemble:apk
-      - |
-        DEVICE='{{.DEVICE_ID | default ""}}'
-        if [ -z "$DEVICE" ]; then
-          DEVICE="${DEVICE_ID:-}"
-        fi
-        if [ -z "$DEVICE" ]; then
-          DEVICE=$("{{.ADB}}" devices | awk 'NR > 1 && $2 == "device" && $1 !~ /^emulator-/ { print $1; exit }')
-        fi
-        if [ -z "$DEVICE" ]; then
-          echo "Error: no connected physical Android device found."
-          echo "Pass DEVICE_ID=<serial> to target a device explicitly."
-          echo "Find connected device serials with: {{.ADB}} devices"
-          exit 1
-        fi
-
-        echo "Deploying {{.BIN_DIR}}/{{.APP_NAME}}.apk to device $DEVICE..."
-        "{{.ADB}}" -s "$DEVICE" uninstall {{.APP_ID}} 2>/dev/null || true
-        "{{.ADB}}" -s "$DEVICE" install "{{.BIN_DIR}}/{{.APP_NAME}}.apk"
-        "{{.ADB}}" -s "$DEVICE" shell am start -n {{.APP_ID}}/com.wails.app.MainActivity
+      - './scripts/android-deploy.sh --apk "{{.BIN_DIR}}/{{.APP_NAME}}.apk" --target device{{if .DEVICE_ID}} --serial "{{.DEVICE_ID}}"{{end}}{{if .APP_ID}} --expect "{{.APP_ID}}"{{end}}'
     preconditions:
       - sh: '[ -x "{{.ADB}}" ] || command -v adb'
         msg: "adb not found. Install the Android SDK platform-tools (or set ANDROID_HOME)"
@@ -430,25 +418,7 @@ tasks:
         vars:
           ARCH: arm64
     cmds:
-      - |
-        DEVICE='{{.DEVICE_ID | default ""}}'
-        if [ -z "$DEVICE" ]; then
-          DEVICE="${DEVICE_ID:-}"
-        fi
-        if [ -z "$DEVICE" ]; then
-          DEVICE=$("{{.ADB}}" devices | awk 'NR > 1 && $2 == "device" && $1 !~ /^emulator-/ { print $1; exit }')
-        fi
-        if [ -z "$DEVICE" ]; then
-          echo "Error: no connected physical Android device found."
-          echo "Pass DEVICE_ID=<serial> to target a device explicitly."
-          echo "Find connected device serials with: {{.ADB}} devices"
-          exit 1
-        fi
-
-        echo "Deploying {{.BIN_DIR}}/{{.APP_NAME}}.apk to device $DEVICE..."
-        "{{.ADB}}" -s "$DEVICE" uninstall {{.APP_ID}} 2>/dev/null || true
-        "{{.ADB}}" -s "$DEVICE" install "{{.BIN_DIR}}/{{.APP_NAME}}.apk"
-        "{{.ADB}}" -s "$DEVICE" shell am start -n {{.APP_ID}}/com.wails.app.MainActivity
+      - './scripts/android-deploy.sh --apk "{{.BIN_DIR}}/{{.APP_NAME}}.apk" --target device{{if .DEVICE_ID}} --serial "{{.DEVICE_ID}}"{{end}}{{if .APP_ID}} --expect "{{.APP_ID}}"{{end}}'
     preconditions:
       - sh: '[ -x "{{.ADB}}" ] || command -v adb'
         msg: "adb not found. Install the Android SDK platform-tools (or set ANDROID_HOME)"

build/android/app/src/main/java/com/wails/app/MainActivity.java

@@ -891,13 +891,41 @@ public class MainActivity extends AppCompatActivity {
         }
     }
 
+    /**
+     * The activity going away is not the app shutting down.
+     *
+     * <p>The scaffold called {@code bridge.shutdown()} here, which is
+     * the natural reading of onDestroy and is wrong for this app twice
+     * over. Android destroys and recreates an activity for a
+     * configuration change the manifest does not declare, under memory
+     * pressure, and on every background if the user has "Don't keep
+     * activities" on -- all **without restarting the process**. And
+     * when the user really does leave, this app's reason for existing
+     * in the background is that a song is playing, which is what the
+     * {@code mediaPlayback} foreground service is holding the process
+     * alive for. Either way, tearing the Go side down here would stop
+     * the music.
+     *
+     * <p>It was harmless only by accident: {@code nativeShutdown} calls
+     * {@code App.Quit()}, whose Android {@code destroy()} is an empty
+     * method, and {@code Run()}'s deferred {@code shutdownServices()}
+     * can never fire because Android's {@code platformRun} is
+     * {@code select{}} and does not return. So no {@code
+     * ServiceShutdown} has ever run on Android, and removing this call
+     * changes nothing today -- it stops the day someone implements
+     * {@code destroy()} from silently killing playback on a rotation.
+     *
+     * <p>There is no callback for "the process is going away"; Android
+     * simply kills it. Durability on this platform is the persist
+     * writers, which submit on every mutation rather than at exit.
+     *
+     * <p>See #52, and CLAUDE.md, "An activity is a view onto the
+     * process".
+     */
     @Override
     protected void onDestroy() {
         super.onDestroy();
         unregisterSystemEventReceivers();
-        if (bridge != null) {
-            bridge.shutdown();
-        }
         if (webView != null) {
             webView.destroy();
         }

build/android/app/src/main/java/com/wails/app/WailsBridge.java

@@ -129,7 +129,24 @@ public class WailsBridge {
     }
 
     /**
-     * Initialize the native Go library
+     * Initialize the native Go library.
+     *
+     * <p><b>{@code initialized} is deliberately per-instance, and making
+     * it {@code static} is the trap this comment exists for.</b> A
+     * recreated activity builds a new bridge and calls this again, in a
+     * process where the native library is already loaded and Go's
+     * {@code main()} is already running -- so "initialise once per
+     * process" looks like exactly the right rule. It is not, because
+     * {@code nativeInit} does <i>two</i> things: it runs
+     * {@code go mainFunc()}, and it stores the global JNI reference to
+     * <i>this</i> bridge. Skip it and Go keeps executing JavaScript
+     * against the destroyed activity's WebView: the app opens, renders,
+     * and never receives another backend event.
+     *
+     * <p>So this is called every time, and the half that must not repeat
+     * is latched on the Go side instead, at the top of {@code main()} --
+     * which is also where the damage was ({@code os.Exit(1)}), and the
+     * only place that can see it. See #52.
      */
     public void initialize() {
         if (initialized) {

e2e/specs/album-dropdown.spec.ts

@@ -110,27 +110,30 @@ test.describe('the album dropdown', () => {
     await app.setViewportSize({ width: 900, height: 600 });
 
     try {
-      // Wait for the range the assertion below actually needs, not for
-      // "scrollable at all" (#133). The guard used to be
-      // `scrollHeight > clientHeight + 40` while the next line asks to
-      // reach 80, so any range in 41-79 satisfied it and could not
-      // satisfy the assertion — and the grid passes through exactly
-      // that while it settles, because it recomputes its columns after
-      // the resize rather than during it. The settled range here is
-      // 330, so this waits rather than weakening anything.
+      // The container has to be a scroller at all, which is the thing
+      // the defect behind this spec broke and is a property rather
+      // than a moment.
       await expect
         .poll(() => scrollRange(app))
-        .toMatchObject({ room: true, overflowY: 'auto' });
+        .toMatchObject({ overflowY: 'auto' });
 
-      await app.evaluate((target) => {
-        const sc = document
-          .querySelector('cover-grid')
-          ?.shadowRoot?.querySelector('.grid-scroll-container');
-
-        if (sc) sc.scrollTop = target;
-      }, SCROLL_TARGET);
-
-      expect(await scrollTop(app)).toBe(SCROLL_TARGET);
+      // **Scrolling it and reading it back are one round trip** (#151).
+      //
+      // #133 made the guard ask for the range this needs rather than
+      // for "scrollable at all", which was necessary and is not
+      // sufficient: a guard and the write it guards are separate
+      // `evaluate` calls, so the grid can satisfy the range and settle
+      // out of it before the write lands. It still does — observed as
+      // `Expected 80, Received 10` in the second of three consecutive
+      // full-suite runs, with the spec green alone on the same app
+      // straight afterwards.
+      //
+      // Polling harder cannot close a window between two moments; only
+      // removing the window can. So the probe sets `scrollTop` and
+      // returns what it reads back, in one page-side call, and the
+      // poll retries *that* — which also means the assertion is about
+      // what the grid did rather than about what it was ready to do.
+      await expect.poll(() => scrollTo(app, SCROLL_TARGET)).toBe(SCROLL_TARGET);
 
       // And the dropdown it opens is on screen, wherever the manager
       // decides that leaves the scroll. It is *not* "the position is
@@ -261,7 +264,7 @@ async function closeDropdown(app: Page): Promise<void> {
   });
 }
 
-/** Whether the grid can scroll at all, which decides if a probe can move. */
+/** Whether the grid is a scroller at all, which is what the bug broke. */
 async function scrollRange(app: Page) {
   return app.evaluate((target) => {
     const sc = document
@@ -269,22 +272,37 @@ async function scrollRange(app: Page) {
       ?.shadowRoot?.querySelector('.grid-scroll-container');
 
     return {
-      // `room` is the precondition of the assertion that follows it:
-      // enough range to actually reach the target. A threshold below
-      // what the caller depends on is not a guard.
+      // Reported for the failure message rather than waited on: `room`
+      // was the guard #133 strengthened, and #151 is that a guard in
+      // its own round trip cannot speak for the write in the next one.
+      // `scrollTo` below is the assertion now; this says *why* it did
+      // not reach the target when it does not.
       room: !!sc && sc.scrollHeight - sc.clientHeight >= target,
       overflowY: sc ? getComputedStyle(sc).overflowY : '',
     };
   }, SCROLL_TARGET);
 }
 
-async function scrollTop(app: Page): Promise<number> {
-  return app.evaluate(
-    () =>
-      document
+/**
+ * Scroll the grid and report where it actually landed, in one call.
+ *
+ * The whole point is that the set and the read share a moment: a
+ * `scrollTop` write is clamped to the range *at the instant it lands*,
+ * so reading it back in a second round trip asks a container that may
+ * have re-laid out in between.
+ */
+async function scrollTo(app: Page, target: number): Promise<number> {
+  return app.evaluate((to) => {
+    const sc = document
       .querySelector('cover-grid')
-        ?.shadowRoot?.querySelector('.grid-scroll-container')?.scrollTop ?? -1,
-  );
+      ?.shadowRoot?.querySelector('.grid-scroll-container');
+
+    if (!sc) return -1;
+
+    sc.scrollTop = to;
+
+    return sc.scrollTop;
+  }, target);
 }
 
 /** Whether the open dropdown is inside the scroll container's viewport. */

e2e/specs/bottom-bar.spec.ts

@@ -0,0 +1,147 @@
+import { test, expect, callBinding, NO_QUEUE_SOURCE } from '../support/fixtures.js';
+import type { Page } from '@playwright/test';
+
+/**
+ * The bottom bar's two promises (#23, #42): the transport is centred in
+ * the window, and the volume is a slider rather than a popup.
+ *
+ * **"Centred" is measured against the window, not against the space
+ * left over**, which is the whole of #23. The bar was
+ * `320px 1fr auto`, so the transport sat in the middle of what the
+ * metadata and the queue button did not use — its centre was ~140px
+ * right of the window's at every size, which reads as an alignment
+ * mistake rather than as a layout choice.
+ *
+ * The mechanism is that the outer two columns are the same width, so
+ * this asserts the *outcome* (centre lines up) rather than the CSS. A
+ * spec that checked `grid-template-columns` would pass on any build
+ * that kept the declaration and broke the result.
+ */
+
+/** Where the transport sits, against where the window's centre is. */
+const geometry = (app: Page) =>
+  app.evaluate(() => {
+    const bar = document.querySelector<HTMLElement>('.bottom-bar')!;
+    const player = document.querySelector<HTMLElement>('audio-player')!;
+    const b = bar.getBoundingClientRect();
+    const p = player.getBoundingClientRect();
+
+    const seek = player.shadowRoot
+      ?.querySelector('seek-bar')
+      ?.shadowRoot?.querySelector('wa-slider');
+
+    return {
+      offset: Math.round(p.left + p.width / 2 - (b.left + b.width / 2)),
+      barHeight: Math.round(b.height),
+      seekWidth: seek ? Math.round(seek.getBoundingClientRect().width) : -1,
+    };
+  });
+
+/** Something has to be playing before the transport draws a seek bar. */
+async function play(app: Page): Promise<void> {
+  const paths = await app.evaluate(async () => {
+    const tracks = (await window.__yjEvents.call(
+      'library.Library.GetTracks',
+      [0],
+      10_000,
+    )) as { FilePath: string }[];
+
+    return tracks.slice(0, 3).map((t) => t.FilePath);
+  });
+
+  await callBinding(app, 'queue.Queue.SetQueue', [
+    paths,
+    0,
+    false,
+    NO_QUEUE_SOURCE,
+  ]);
+  await callBinding(app, 'queue.Queue.Play');
+  await expect(app.getByTestId('now-playing-title')).not.toBeEmpty();
+}
+
+test.describe('the bottom bar', () => {
+  test.afterEach(async ({ app }) => {
+    await callBinding(app, 'queue.Queue.Clear').catch(() => {
+      /* already empty */
+    });
+    await app.setViewportSize({ width: 1440, height: 900 });
+  });
+
+  /**
+   * Four widths, because a centring bug is a function of width: the old
+   * layout was off by half the difference between the two outer
+   * columns, so it was wrong by a different amount at each one and
+   * exactly right at none.
+   */
+  for (const width of [800, 900, 1100, 1440]) {
+    test(`centres the transport in the window at ${width}px`, async ({
+      app,
+    }) => {
+      await app.setViewportSize({ width, height: 700 });
+      await play(app);
+
+      await expect.poll(() => geometry(app).then((g) => g.offset)).toBe(0);
+    });
+  }
+
+  /**
+   * The seek bar is what the centring is *paid for* with, so it is
+   * asserted rather than assumed.
+   *
+   * Reserving the metadata's full width on both sides centres the
+   * transport perfectly and squeezes the control you drag: measured
+   * during this work at **61px of track at 800px**, against 257 before
+   * the change. The side columns are capped at a quarter of the bar for
+   * that reason, and this is the number that says so — 246 at 800px,
+   * which is parity with the uncentred layout.
+   */
+  test('does not pay for the centring with the seek bar', async ({ app }) => {
+    await app.setViewportSize({ width: 800, height: 700 });
+    await play(app);
+
+    await expect
+      .poll(() => geometry(app).then((g) => g.seekWidth))
+      .toBeGreaterThan(200);
+  });
+
+  /**
+   * #42: the slider is simply there. Three gestures — click open, drag,
+   * click closed — is what a bottom bar has room not to ask for.
+   */
+  test('shows the volume slider without a click', async ({ app }) => {
+    await app.setViewportSize({ width: 1440, height: 900 });
+
+    const volume = app.locator('.bottom-bar volume-control');
+
+    await expect(volume).toBeVisible();
+    await expect(volume.locator('wa-slider')).toBeVisible();
+  });
+
+  /**
+   * And the inline icon is the mute toggle, because with the slider
+   * beside it there is nothing left to disclose. The name follows the
+   * action rather than the state for the same reason.
+   */
+  test('names the inline icon after what it does', async ({ app }) => {
+    await app.setViewportSize({ width: 1440, height: 900 });
+
+    await expect(
+      app.locator('.bottom-bar volume-control').getByRole('button', {
+        name: 'Mute',
+      }),
+    ).toBeVisible();
+  });
+
+  /**
+   * The bar is a fixed 4em row and the transport sits in it. A slider
+   * with a label grows `#slider` by 8px unless `wa-slider-label.css`
+   * suppresses it, which moved the whole bar the last time — so the
+   * height is pinned here rather than left to a screenshot.
+   */
+  test('stays 4em tall', async ({ app }) => {
+    await app.setViewportSize({ width: 1440, height: 900 });
+    await play(app);
+
+    await expect.poll(() => geometry(app).then((g) => g.barHeight)).toBe(64);
+  });
+});

e2e/specs/control-names.spec.ts

@@ -29,18 +29,13 @@ test.describe('a control says what it controls', () => {
   });
 
   test('the volume slider is announced as Volume', async ({ app }) => {
-    // The popup renders no slider at all while closed, the same way the
-    // queue panel renders no list — so this has to open it first.
-    await app.getByRole('button', { name: /volume/i }).click();
-
+    // No disclosure to open first, and no state to put back afterwards:
+    // #42 made the slider inline, so it is simply there. The assertion
+    // is unchanged — the *name* is the subject here, and the route to
+    // the control got shorter rather than different.
     await expect(
       app.getByRole('slider', { name: 'Volume' }),
     ).toBeVisible();
-
-    // Leave the transport as it was found: the specs share one page in
-    // file order, and an open popup covers the buttons beneath it.
-    await app.keyboard.press('Escape');
-    await app.locator('body').click({ position: { x: 5, y: 5 } });
   });
 
   test('naming the slider did not move the transport', async ({ app }) => {

e2e/specs/failure-voice.spec.ts

@@ -36,9 +36,16 @@ test.describe('a failed binding says so', () => {
     // Libraries is the one section that starts expanded (H-22), so ask
     // the disclosure what state it is in rather than assuming one — a
     // blind click used to expand it and now collapses it.
+    //
+    // By role and name, not by `.header`: since #27 the section also
+    // contains a `job-panel`, and an open `job-details-drawer` inside
+    // it carries the same class. That only bites once a job exists,
+    // which is why it showed up on the *second* engine of a CI run and
+    // not the first.
     const disclosure = page
       .locator('config-section[heading="Libraries"]')
-      .locator('.header');
+      .getByRole('button', { name: 'Libraries' })
+      .first();
 
     if ((await disclosure.getAttribute('aria-expanded')) === 'false') {
       await disclosure.click();

e2e/specs/jobs-in-settings.spec.ts

@@ -0,0 +1,124 @@
+import { test, expect, waitForEvent } from '../support/fixtures.js';
+
+/**
+ * The Jobs tab folded into the places the work is started (#27).
+ *
+ * The assertion worth making is not that the tab is gone — that is one
+ * line of a table — but that **nothing became unreachable when it
+ * went**. Scanning is the case that mattered: the per-library controls
+ * lived only on that page, and the tab's own comment says they had been
+ * moved there out of Settings in the first place.
+ *
+ * `#24` wrote down one sentence covering all three size bands: *no
+ * action is ever unreachable at any supported size*. Deleting a
+ * destination is exactly the change that can quietly break it.
+ */
+type Page = import('@playwright/test').Page;
+
+const section = (page: Page, heading: string) =>
+  page.locator(`config-page config-section[heading="${heading}"]`);
+
+async function openSettings(page: Page, heading: string): Promise<void> {
+  await page.getByTestId('nav-settings').click();
+
+  // The section's own disclosure, by role rather than by `.header`:
+  // an open Libraries section also contains `job-details-drawer`,
+  // whose own header matches that class and makes it ambiguous.
+  const header = section(page, heading)
+    .getByRole('button', { name: heading })
+    .first();
+
+  await expect(header).toBeVisible();
+
+  if ((await header.getAttribute('aria-expanded')) === 'false') {
+    await header.click();
+  }
+
+  await expect(header).toHaveAttribute('aria-expanded', 'true');
+}
+
+test.describe('background jobs live where the work is started', () => {
+  test('the Jobs destination is gone', async ({ app }) => {
+    await expect(app.getByTestId('nav-jobs')).toHaveCount(0);
+
+    // And it is not offered as a launch page either, which is the copy
+    // of the destination list that is easiest to forget.
+    await openSettings(app, 'General');
+
+    const options = await section(app, 'General')
+      .locator('select')
+      .first()
+      .locator('option')
+      .allTextContents();
+
+    expect(options).not.toContain('Jobs');
+  });
+
+  /**
+   * Scanning is startable from Settings → Libraries, and the job that
+   * results is visible there with its controls. One assertion covers
+   * both halves, because a Scan All that started nothing would leave
+   * the panel empty and read exactly like a panel that does not work.
+   */
+  test('a scan is started and watched in Settings', async ({ app }) => {
+    await openSettings(app, 'Libraries');
+
+    const libraries = section(app, 'Libraries');
+
+    await libraries.getByRole('button', { name: 'Scan All' }).click();
+
+    await waitForEvent(app, 'LibraryScanComplete', { timeoutMs: 60_000 });
+
+    const panel = libraries.locator('job-panel');
+
+    await expect(panel.locator('job-row')).toHaveCount(1, { timeout: 10_000 });
+
+    // The generic affordances are the point of the panel: the tier
+    // list and the progress rings the other surfaces already had
+    // cannot open a log.
+    await expect(
+      panel.getByRole('button', { name: /^Details/ }),
+    ).toBeVisible();
+  });
+
+  /** A finished job dismisses from where it is shown. */
+  test('a finished scan can be dismissed in place', async ({ app }) => {
+    await openSettings(app, 'Libraries');
+
+    const panel = section(app, 'Libraries').locator('job-panel');
+    const dismiss = panel.getByRole('button', { name: /^Dismiss/ }).first();
+
+    await expect(dismiss).toBeVisible({ timeout: 10_000 });
+    await dismiss.click();
+
+    await expect(panel.locator('job-row')).toHaveCount(0);
+  });
+
+  /**
+   * Full rescan is destructive and asks first. It is asserted at the
+   * dialog rather than through it — running one against the seeded app
+   * would delete the library the rest of the suite reads.
+   */
+  test('Full Rescan asks before it does anything', async ({ app }) => {
+    await openSettings(app, 'Libraries');
+
+    await section(app, 'Libraries')
+      .getByRole('button', { name: 'Full Rescan' })
+      .click();
+
+    const dialog = app.getByRole('dialog', { name: 'Full rescan' });
+
+    await expect(dialog).toBeVisible();
+
+    // The message is read off the *host*, not the dialog: a wa-dialog
+    // keeps its slotted content in the host's shadow root, so
+    // `toContainText` on the dialog itself sees only Web Awesome's
+    // chrome.
+    await expect(app.locator('confirm-dialog')).toContainText(
+      'deletes all library data',
+    );
+
+    await app.getByRole('button', { name: 'Cancel' }).click();
+    await expect(dialog).toBeHidden();
+  });
+});

e2e/specs/layout-overflow.spec.ts

@@ -33,6 +33,14 @@ const VIEWPORTS = [
   // was missing its own worst case.
   { name: '900×600 (the widest sidebar, so the narrowest content)', width: 900, height: 600 },
   { name: `the minimum (${MIN_VIEWPORT.width}×${MIN_VIEWPORT.height})`, ...MIN_VIEWPORT },
+  // Below the enforced minimum on purpose, and for the reason 700×480
+  // is below it further down: a scaled display or a large system font
+  // lands the layout here without the window ever being dragged there,
+  // and 600 is the last width before the phone layout takes over. The
+  // *narrowest header* is a different question from the narrowest
+  // content area and has a different answer — this one (#143), where
+  // the bar was 611px inside 600 sitting still.
+  { name: '600×600 (the bottom of the Compact band)', width: 600, height: 600 },
 ];
 
 /**
@@ -93,9 +101,10 @@ test.describe('the app fits in its own window', () => {
       )
       .toBe(true);
 
-    // Settings and Jobs are the two that were unreachable: they are
-    // last in the nav, and the pane used to clip rather than scroll.
-    for (const view of ['jobs', 'settings'] as const) {
+    // Settings is the one that was unreachable: it is last in the nav,
+    // and the pane used to clip rather than scroll. (Jobs was the other
+    // half of this until #27 folded it into Settings.)
+    for (const view of ['explore', 'settings'] as const) {
       const item = app.getByTestId(`nav-${view}`);
 
       await item.scrollIntoViewIfNeeded();
@@ -123,7 +132,16 @@ test.describe('the app fits in its own window', () => {
     // be dragged here, but a scaled display or a large system font can
     // still land the layout in it, and clipping the nav with no scroll
     // is the failure that made Settings unreachable.
-    const reachable = await app.locator('app-sidebar').evaluate((el) => {
+    //
+    // The scroll and the measurement share one `evaluate` — #151's
+    // rule, which this already had — and the whole probe is polled,
+    // which it did not: a viewport change settles asynchronously, so a
+    // single attempt reads whatever the sidebar happened to be doing.
+    // The probe is safe to repeat because scrolling to the bottom twice
+    // is scrolling to the bottom.
+    await expect
+      .poll(() =>
+        app.locator('app-sidebar').evaluate((el) => {
           const settings = el.shadowRoot?.querySelector<HTMLElement>(
             '[data-testid="nav-settings"]',
           );
@@ -135,15 +153,24 @@ test.describe('the app fits in its own window', () => {
           const item = settings.getBoundingClientRect();
           const pane = el.getBoundingClientRect();
 
-      return item.bottom <= Math.ceil(pane.bottom) && item.top >= Math.floor(pane.top);
-    });
-
-    expect(reachable).toBe(true);
+          return (
+            item.bottom <= Math.ceil(pane.bottom) &&
+            item.top >= Math.floor(pane.top)
+          );
+        }),
+      )
+      .toBe(true);
   });
 });
 
 test.describe('the title block fits its bar', () => {
   test('the hgroup stays inside the 4em top bar', async ({ app }) => {
+    // Stated rather than inherited from whatever ran last. Since #143
+    // the wordmark is visually hidden at widths where the bar cannot
+    // afford it, so a test about its *vertical* fit has to say which
+    // width it is asking about.
+    await app.setViewportSize({ width: 1440, height: 900 });
+
     // The state a11y.29 landed in. The pair is flex-centred and a UA
     // gives an `h1` a 0.67em top margin, so the block measured 67px
     // inside 64 — pre-existing, and invisible until dropping the h3's
@@ -245,16 +272,26 @@ test.describe('the shell reflows rather than hiding what does not fit', () => {
     test(`no scrollbar appears at ${vp.name}`, async ({ app }) => {
       await app.setViewportSize({ width: vp.width, height: vp.height });
 
-      const excess = await app.evaluate(() => {
+      // Polled, for the reason the track-row test above is: since #143
+      // the top bar's fit is *measured* — a ResizeObserver decides what
+      // it can afford at this width — so a single read taken straight
+      // after the resize races the observer and reports the frame
+      // before it. Read once, this passed alone and failed in the full
+      // suite, which is the shape of a timing assumption rather than of
+      // a defect.
+      //
+      // The other half of the assertion: at every size this app
+      // promises, the fix costs nothing. A scrollbar that is always
+      // there is a worse answer than the clipping it replaced.
+      await expect
+        .poll(() =>
+          app.evaluate(() => {
             const de = document.documentElement;
 
             return de.scrollWidth - de.clientWidth;
-      });
-
-      // The other half: at every size this app promises, the fix costs
-      // nothing. A scrollbar that is always there is a worse answer
-      // than the clipping it replaced.
-      expect(excess).toBe(0);
+          }),
+        )
+        .toBe(0);
     });
   }
 });

e2e/specs/offline-icons.spec.ts

@@ -28,7 +28,7 @@ const EXPECTED_MIN_ICONS = 5;
 
 const VIEWS = [
   'home', 'tracks', 'albums', 'artists', 'genres', 'playlists',
-  'explore', 'downloads', 'jobs', 'settings',
+  'explore', 'downloads', 'autotag', 'settings',
 ];
 
 type IconState = { name: string; hasSvg: boolean };

e2e/specs/page-header.spec.ts

@@ -1,4 +1,4 @@
-import { test, expect } from '../support/fixtures.js';
+import { test, expect, navigateTo } from '../support/fixtures.js';
 
 /**
  * H-19: Playlists, Downloads, Jobs, Settings and Home had a page
@@ -21,7 +21,6 @@ const VIEWS: [string, string, boolean][] = [
   ['tracks', 'Tracks', true],
   ['explore', 'Explore', false],
   ['downloads', 'Downloads', false],
-  ['jobs', 'Background jobs', false],
 ];
 
 /** The header lives in the view's shadow root, inside its own. */
@@ -53,13 +52,16 @@ const TAGS: Record<string, string> = {
   tracks: 'track-list',
   explore: 'explore-view',
   downloads: 'downloads-view',
-  jobs: 'jobs-view',
 };
 
 test.describe('every primary view says what it is', () => {
   test('each one has the shared header, with a heading', async ({ app }) => {
+    // By event rather than by nav item: a destination is not
+    // guaranteed to have one any more (#25 — Downloads is absent
+    // without a download client), and every one of these is still a
+    // primary view with a header, which is what this spec is about.
     for (const [view, heading, hasCount] of VIEWS) {
-      await app.getByTestId(`nav-${view}`).click();
+      await navigateTo(app, view);
       await expect(app.getByTestId('main-content')).toHaveAttribute(
         'data-active-view',
         view,

e2e/specs/phone-shell.spec.ts

@@ -1,4 +1,4 @@
-import { test, expect } from '../support/fixtures.js';
+import { test, expect, LONG_TRACK } from '../support/fixtures.js';
 
 /**
  * The phone shell (plan 016 B2, phase 1).
@@ -138,6 +138,78 @@ test.describe('the shell on a phone', () => {
       .toHaveAttribute('data-active-view', 'tracks');
   });
 
+  /**
+   * The same journey with a track that has **no cover art** (#150).
+   *
+   * The test above starts the *first* row of the track list, so which
+   * track it plays is the order the scan inserted them in — and the
+   * answer decided whether it passed. A track with artwork renders an
+   * `<img>`, which is no obstacle; one without renders a placeholder
+   * `wa-icon`, which took every click aimed at the button beneath it,
+   * because that button is absolutely positioned with `z-index: auto`
+   * and the art is a *later* sibling. They tied, and the later one won.
+   *
+   * So this picks a track *for* the property that broke it, which is
+   * the only way the assertion means anything: the version above passes
+   * on a broken build roughly two runs in three, which is exactly how
+   * it came to cost three CI cycles across two branches that could not
+   * have caused it.
+   */
+  test('opens the full-screen now playing for a track with no art', async ({
+    app,
+  }) => {
+    // `LONG_TRACK` by name, and not "the first track with no
+    // CoverArt": the *library* model reports that field empty for
+    // every row in this fixture (31 of 31), so filtering on it selects
+    // nothing in particular and picked a 2-second track, which had
+    // finished before the assertions ran. The placeholder check below
+    // is what actually holds the property this test needs.
+    const started = await app.evaluate(async (longTitle) => {
+      const tracks = (await window.__yjEvents.call(
+        'library.Library.GetTracks',
+        [0],
+        10_000,
+      )) as { FilePath: string; TrackName: string }[];
+
+      const bare = tracks.find((t) => t.TrackName === longTitle);
+
+      if (!bare) return null;
+
+      await window.__yjEvents.call(
+        'queue.Queue.SetQueue',
+        [[bare.FilePath], 0, false, { type: '', id: 0, label: '' }],
+        10_000,
+      );
+      await window.__yjEvents.call('queue.Queue.Play', [], 5_000);
+
+      return bare.TrackName;
+    }, LONG_TRACK);
+
+    expect(started).toBe(LONG_TRACK);
+
+    await expect(app.getByTestId('now-playing-title')).not.toBeEmpty();
+
+    // **The placeholder is the whole point**, so it is asserted rather
+    // than assumed: this test is about the thing that renders when
+    // there is no artwork. If the fixture ever gives this album a
+    // cover, this fails and says so instead of passing while measuring
+    // the easy case.
+    //
+    // One selector rather than a chain from the host: Playwright's CSS
+    // engine pierces an open shadow root, and chaining from the host
+    // element does not reach into it.
+    await expect(
+      app.locator('now-playing .cover-placeholder'),
+    ).toBeAttached();
+
+    await app.getByTestId('open-now-playing').click();
+
+    await expect(app.getByTestId('main-content'))
+      .toHaveAttribute('data-active-view', 'now-playing');
+
+    await app.getByTestId('npv-back').click();
+  });
+
   test('offers no way in on a desktop, where the bar is whole', async ({ app }) => {
     await app.setViewportSize({ width: 1440, height: 900 });
 
@@ -154,9 +226,26 @@ test.describe('the shell on a phone', () => {
     await expect(app.locator('now-playing')).toBeVisible();
 
     // Volume is the hardware keys' job on a phone, and a 4px seek bar
-    // is not a thumb target -- both belong to a later phase's
-    // full-screen now-playing view.
-    await expect(app.locator('audio-player volume-control')).toBeHidden();
+    // is not a thumb target -- both belong to the full-screen
+    // now-playing view.
+    //
+    // `.bottom-bar volume-control`, not `audio-player volume-control`:
+    // #42 moved the control out of that component and into the bar, and
+    // **the old locator would have kept passing** — `toBeHidden()` is
+    // satisfied by an element that does not exist, so this assertion
+    // would have gone on reporting success about nothing. Its partner
+    // below is what makes this one mean something.
+    await expect(app.locator('.bottom-bar volume-control')).toBeHidden();
+
+    // The element is there and hidden, rather than absent: the check
+    // above cannot tell those apart on its own.
+    await expect(app.locator('.bottom-bar volume-control')).toHaveCount(1);
+
+    // And the seek bar is still inside the transport, where it stands
+    // down by its own media query.
+    await expect(
+      app.locator('audio-player').locator('seek-bar'),
+    ).toBeHidden();
   });
 });
 

e2e/specs/queue-selection.spec.ts

@@ -0,0 +1,299 @@
+import {
+  test,
+  expect,
+  callBinding,
+  navigateTo,
+  LONG_TRACK,
+  NO_QUEUE_SOURCE,
+} from '../support/fixtures.js';
+import type { Page } from '@playwright/test';
+
+/**
+ * The queue panel's mouse model (#43): single click selects, ctrl and
+ * shift extend, double click plays from that row.
+ *
+ * **All four already worked, and nothing pinned any of them** — which is
+ * the whole reason the report could be made and could not be settled.
+ * `queue-reorder.spec.ts` covers the keyboard, `queue-overlay.spec.ts`
+ * covers the panel's mode, and the component tier has the reorder
+ * arithmetic; the pointer path had no coverage in either tier, so
+ * "selection is broken here" and "selection is fine here" were equally
+ * consistent with a green suite.
+ *
+ * Two things this spec is deliberately shaped around.
+ *
+ * **The clicks are real.** A `dispatchEvent(new MouseEvent('click'))`
+ * on a row exercises the delegated handler and *not* the question being
+ * asked, which is what the pointer lands on: the rows carry
+ * `explore-link` names that take their own clicks, and a synthetic
+ * event aimed at the row reports a selection the mouse would never have
+ * produced. Every click here goes through Playwright.
+ *
+ * **The playing assertions use the 90-second fixture.** Every other
+ * track is 2–6 seconds, so "double click plays row 3" read against a
+ * 2-second track reports whatever auto-advance moved on to — measured
+ * during this work as row 3 double-clicked and row 4 playing, which
+ * reads exactly like an off-by-one in `PlayIndex` and is not one.
+ */
+
+/**
+ * How long a click may take to show up as a highlight.
+ *
+ * **A poll with the default 5s timeout cannot see this defect**, and
+ * that is the point of naming it. `queue-panel` repaints its rows two
+ * ways — `onSelectionChanged()` calls `virtualizer.requestUpdate()`,
+ * and `.keyFunction` is a per-render arrow, which is itself a changed
+ * property the virtualizer reacts to. With **both** removed the
+ * highlight still arrives, on whatever unrelated render happens next:
+ * measured at 134ms, 3,866ms and 5,816ms for three clicks, against
+ * 5ms, 16ms and 17ms on a healthy build.
+ *
+ * A user cannot tell "four seconds late" from "broken", which is very
+ * close to what this issue reports. So the assertion is that the
+ * highlight is *prompt*, with a bound ~30x the measured healthy case
+ * and an order of magnitude under the degraded one.
+ */
+const HIGHLIGHT_MS = 500;
+
+/** The queue's own answer, never the DOM's. */
+async function playing(app: Page): Promise<{ index: number; title: string }> {
+  const state = await callBinding<{
+    currentIndex: number;
+    tracks: { title: string }[];
+  }>(app, 'queue.Queue.GetState');
+
+  return {
+    index: state.currentIndex,
+    title: state.tracks[state.currentIndex]?.title ?? '',
+  };
+}
+
+/** Which rows are selected, as the accessibility tree sees it. */
+const selected = (app: Page) =>
+  app.evaluate(() =>
+    [
+      ...document
+        .querySelector('queue-panel')!
+        .shadowRoot!.querySelectorAll('[data-index]'),
+    ]
+      .filter((row) => row.getAttribute('aria-selected') === 'true')
+      .map((row) => Number((row as HTMLElement).dataset['index'])),
+  );
+
+/**
+ * Six tracks with the long one in the middle, so a "play from here"
+ * assertion has something to land on that will still be playing when it
+ * is read back.
+ */
+async function queueSixAndOpen(app: Page): Promise<void> {
+  const paths = await app.evaluate(async (longTitle) => {
+    // `TrackName`, not `Title`: the library model names it after the
+    // tag, and the *queue* is what calls it `title`.
+    const tracks = (await window.__yjEvents.call(
+      'library.Library.GetTracks',
+      [0],
+      10_000,
+    )) as { FilePath: string; TrackName: string; Album: string }[];
+
+    const long = tracks.find((t) => t.TrackName === longTitle);
+
+    /**
+     * **Tracks that have an album**, which is a requirement of one of
+     * the tests and was previously left to luck (#156).
+     *
+     * `explore-link` routes a track name to its *album's* page, so a
+     * track with no album renders a name that navigates nowhere — and
+     * the fixture library deliberately contains two (`01 Tone A`,
+     * `02 Tone B`). Which tracks arrive first is `audio_files.id`
+     * order, i.e. the order the **scan** inserted them, which depends
+     * on concurrency and directory traversal: locally the first eight
+     * all had albums and the spec passed twice over, and CI rebuilds
+     * its seed with a real scan and got a different eight.
+     *
+     * Asking for what the test needs is the fix. It is not a
+     * narrowing: every assertion here wants an ordinary track, and
+     * "the first five rows" was never a way to ask for one in a
+     * library whose whole purpose is edge cases.
+     */
+    const rest = tracks
+      .filter((t) => t.TrackName !== longTitle && t.Album !== '')
+      .slice(0, 5);
+
+    // Index 3 is the long one: far enough down that a shift-extend has
+    // room either side of it.
+    return [
+      ...rest.slice(0, 3).map((t) => t.FilePath),
+      long!.FilePath,
+      ...rest.slice(3).map((t) => t.FilePath),
+    ];
+  }, LONG_TRACK);
+
+  await callBinding(app, 'queue.Queue.SetQueue', [
+    paths,
+    0,
+    false,
+    NO_QUEUE_SOURCE,
+  ]);
+
+  // A closed panel renders no list at all.
+  await app.locator('#queue-button').click();
+  await expect(app.locator('queue-panel .track-item').first()).toBeVisible();
+  await expect(app.locator('queue-panel .track-item')).toHaveCount(6);
+}
+
+/** The row at a data-index, not the nth child: see the note in the file. */
+const row = (app: Page, index: number) =>
+  app.locator(`queue-panel .track-item[data-index="${index}"]`);
+
+test.describe('selecting in the queue with a mouse', () => {
+  // The suite shares one backend in file order, and a queue and an open
+  // panel both outlive the page. `queue-reorder.spec.ts` sets the
+  // precedent and the reason: a spec that spends state fails the next
+  // one, in a list that reads like a regression in whatever you hold.
+  test.afterEach(async ({ app }) => {
+    await callBinding(app, 'queue.Queue.Clear').catch(() => {
+      /* an empty queue is the state we were asking for */
+    });
+
+    const open = await app.locator('queue-panel[open]').count();
+
+    if (open > 0) await app.locator('#queue-button').click();
+  });
+
+  test('a single click selects that row and only that row', async ({ app }) => {
+    await queueSixAndOpen(app);
+
+    await row(app, 1).click();
+    await expect
+      .poll(() => selected(app), { timeout: HIGHLIGHT_MS })
+      .toEqual([1]);
+
+    // And it *replaces* rather than accumulating, which is the half a
+    // test of one click cannot see.
+    await row(app, 4).click();
+    await expect
+      .poll(() => selected(app), { timeout: HIGHLIGHT_MS })
+      .toEqual([4]);
+  });
+
+  test('ctrl adds a row and shift extends a range', async ({ app }) => {
+    await queueSixAndOpen(app);
+
+    await row(app, 1).click();
+    await row(app, 3).click({ modifiers: ['Control'] });
+    await expect
+      .poll(() => selected(app), { timeout: HIGHLIGHT_MS })
+      .toEqual([1, 3]);
+
+    // From the last row touched, so 3→5, keeping the ctrl-picked 1.
+    await row(app, 5).click({ modifiers: ['Shift'] });
+    await expect
+      .poll(() => selected(app), { timeout: HIGHLIGHT_MS })
+      .toEqual([1, 3, 4, 5]);
+
+    // A plain click collapses the whole thing back to one.
+    await row(app, 2).click();
+    await expect
+      .poll(() => selected(app), { timeout: HIGHLIGHT_MS })
+      .toEqual([2]);
+  });
+
+  test('a double click plays from that row', async ({ app }) => {
+    await queueSixAndOpen(app);
+
+    // Row 3 is the 90-second track. Asked of the backend, because the
+    // panel's own highlight is a different claim.
+    await row(app, 3).dblclick();
+
+    await expect.poll(() => playing(app)).toEqual({
+      index: 3,
+      title: LONG_TRACK,
+    });
+
+    // Playing is not selecting: the double click clears the selection
+    // it made on the way through, or every play leaves a row looking
+    // picked out for an action the user did not ask for.
+    await expect.poll(() => selected(app)).toEqual([]);
+  });
+
+  /**
+   * The one collision the report is actually about.
+   *
+   * Every track, album and artist name in the app navigates
+   * (`utils/explore-link.ts`), and it does that by **stopping the
+   * click's propagation** — in its own words, "the row must not also
+   * treat it as a selection". So a click that lands on the name text
+   * navigates and selects nothing, in the queue panel and in the track
+   * list alike.
+   *
+   * That is deliberate and it is pinned here rather than argued with,
+   * because the measurement says the queue is not the surface where it
+   * hurts: a horizontal hit-scan of a row at three heights makes the
+   * queue row **12%** link and the track list's row **21%** — the panel
+   * the report calls broken is *less* covered by links than the list it
+   * calls correct. What is left is one deliberate exception, and a
+   * change to it should have to fail a test.
+   */
+  test('a click on a name navigates instead, and that is the exception', async ({
+    app,
+  }) => {
+    await queueSixAndOpen(app);
+
+    await row(app, 1).click();
+    await expect
+      .poll(() => selected(app), { timeout: HIGHLIGHT_MS })
+      .toEqual([1]);
+
+    // `.track-title .explore-link`, not `.explore-link` first(): a row
+    // has two, and which one `first()` finds depends on whether the
+    // *title* is a link at all. It is not, for a track with no album —
+    // `explore-link` renders plain text where it cannot route — so the
+    // loose locator silently clicked the **artist** instead and the
+    // assertion below was about a different destination than the one
+    // being exercised (#156).
+    await row(app, 2).locator('.track-title .explore-link').click();
+
+    await expect(app.getByTestId('main-content')).toHaveAttribute(
+      'data-active-view',
+      'explore-album-details',
+    );
+
+    // Row 2 did not join the selection — the link took the click.
+    await expect.poll(() => selected(app)).toEqual([1]);
+
+    await navigateTo(app, 'tracks');
+  });
+
+  /**
+   * And the other half of that bargain: the link holds its navigation
+   * for one double-click interval and drops it if a second click
+   * arrives, so double-clicking a *name* still plays the row rather
+   * than navigating away from it. That is what makes the exception
+   * above survivable, and it is the part most likely to break silently
+   * if the grace interval is ever removed.
+   */
+  test('a double click on a name plays rather than navigating', async ({
+    app,
+  }) => {
+    await queueSixAndOpen(app);
+
+    // Read rather than assumed: which view the app lands on is the
+    // user's `DefaultPage`, so naming one here would be asserting on a
+    // config value in a test about a double click.
+    const before = await app
+      .getByTestId('main-content')
+      .getAttribute('data-active-view');
+
+    await row(app, 3).locator('.explore-link').first().dblclick();
+
+    await expect.poll(() => playing(app)).toEqual({
+      index: 3,
+      title: LONG_TRACK,
+    });
+
+    await expect(app.getByTestId('main-content')).toHaveAttribute(
+      'data-active-view',
+      before!,
+    );
+  });
+});

e2e/specs/settings-reach.spec.ts

@@ -1,4 +1,4 @@
-import { test, expect } from '../support/fixtures.js';
+import { test, expect, navigateTo } from '../support/fixtures.js';
 
 /**
  * Plan 007 phase 5: a11y.1 and a11y.2, frozen against the real app.
@@ -18,16 +18,19 @@ test.describe('Settings is reachable without a mouse', () => {
   }) => {
     await app.getByTestId('nav-settings').click();
 
-    const headers = app.locator('config-page config-section .header');
+    // Per *section*, not per `.header`: a section holding a
+    // `job-panel` (#27) also contains `job-details-drawer`, whose own
+    // header carries that class and is not a disclosure.
+    const sections = app.locator('config-page config-section');
 
-    await expect(headers.first()).toBeVisible();
+    await expect(sections.first()).toBeVisible();
 
-    const count = await headers.count();
+    const count = await sections.count();
 
     expect(count).toBeGreaterThan(4);
 
     for (let i = 0; i < count; i++) {
-      const header = headers.nth(i);
+      const header = sections.nth(i).locator('.header').first();
 
       expect(await header.evaluate((el) => el.tagName)).toBe('BUTTON');
       expect(['true', 'false']).toContain(
@@ -56,7 +59,9 @@ test.describe('Settings is reachable without a mouse', () => {
 
 test.describe("Downloads' tabs are tabs", () => {
   test('arrow keys move the selection and swap the panel', async ({ app }) => {
-    await app.getByTestId('nav-downloads').click();
+    // By event, not by nav item: with no download client configured
+    // there is no Downloads destination to click (#25).
+    await navigateTo(app, 'downloads');
 
     const view = app.locator('downloads-view');
     const requests = view.getByRole('tab', { name: 'Requests' });

e2e/specs/top-bar-fit.spec.ts

@@ -0,0 +1,207 @@
+import { test, expect } from '../support/fixtures.js';
+
+/**
+ * The top bar fits the window it is in (#143).
+ *
+ * **This is measured per child, not on the shell**, which is #69's
+ * lesson repeated one component over: `layout-overflow.spec.ts` asserts
+ * the *document* needs no sideways scrolling, and clipping inside a
+ * component is invisible to it — which is exactly why that spec was
+ * green throughout this defect. What a user sees is a control rendered
+ * past the edge of the bar it belongs to, so that is what is asserted.
+ *
+ * **And it is measured with a job running**, which is the half the
+ * original report missed. `job-indicator` is `hidden` while idle and up
+ * to 235px wide when it is not, so the bar was 611px inside 600 sitting
+ * still and 862px during a scan — 171 to 262px of overflow, arriving
+ * exactly when a user has reason to look at that bar. Nothing else in
+ * this suite has ever measured a layout with work in flight;
+ * `/__test/emit` stages it without staging the scan.
+ */
+type Page = import('@playwright/test').Page;
+
+/**
+ * The widths this asks about.
+ *
+ * 600 is the bottom of the Compact band (#24) and where the defect
+ * lands; 899 and 900 straddle `nav-history` appearing (68px more to
+ * find, at the width that just gained the sidebar's labels); 800 is the
+ * enforced minimum; 390 is a phone, where the answer must be that
+ * nothing collapses because the media queries already did the work.
+ */
+const WIDTHS = [390, 600, 800, 899, 900, 1440];
+
+/**
+ * A scan whose title is as long as a real one gets. The label is capped
+ * at 12rem by the component, so this is the widest the indicator can
+ * be — measuring with "Scanning" instead reports a bar that fits and a
+ * defect that is 100px smaller than it is.
+ */
+const LONG_JOB = {
+  id: 'top-bar-fit',
+  kind: 'library-scan',
+  state: 'running',
+  title: 'Scanning Music from the external drive',
+  current: 40,
+  total: 100,
+};
+
+/**
+ * Every child's right edge against the bar's own content box.
+ *
+ * The content box, not `clientWidth`: the bar has a 2em right gutter,
+ * and a control sitting in the padding is already the failure — it is
+ * simply one that `scrollWidth` under-reports, because `scrollWidth`
+ * counts the left padding and not the right.
+ */
+const overflowingChildren = (page: Page) =>
+  page.evaluate(() => {
+    const bar = document.querySelector<HTMLElement>('header.top-bar')!;
+    const style = getComputedStyle(bar);
+    const box = bar.getBoundingClientRect();
+    const left = box.left + parseFloat(style.paddingLeft);
+    const right = box.right - parseFloat(style.paddingRight);
+
+    return [...bar.children]
+      .filter((child) => {
+        const cs = getComputedStyle(child);
+
+        // Out of flow is out of the question: a collapsed wordmark is
+        // `position: absolute` and 1px wide precisely so it costs the
+        // row nothing.
+        if (cs.display === 'none' || cs.position === 'absolute') return false;
+
+        const r = child.getBoundingClientRect();
+
+        return r.width > 0 && (r.right > right + 0.5 || r.left < left - 0.5);
+      })
+      .map((child) => {
+        const r = child.getBoundingClientRect();
+
+        return `${child.tagName.toLowerCase()}: ${Math.round(r.left)}..${Math.round(r.right)} outside ${Math.round(left)}..${Math.round(right)}`;
+      });
+  });
+
+/** What the fit pass gave up, read back off the DOM it changed. */
+const collapsed = (page: Page) =>
+  page.evaluate(() => ({
+    wordmark: !!document.querySelector('header.top-bar hgroup.yj-collapsed'),
+    jobLabel: !!document.querySelector('job-indicator[compact]'),
+  }));
+
+test.describe('the top bar fits the window', () => {
+  for (const width of WIDTHS) {
+    test(`no control sits outside the bar at ${width}px, idle`, async ({
+      app,
+    }) => {
+      await app.setViewportSize({ width, height: 600 });
+
+      await expect.poll(() => overflowingChildren(app)).toEqual([]);
+    });
+
+    test(`no control sits outside the bar at ${width}px, with a job running`, async ({
+      app,
+      testctl,
+    }) => {
+      await app.setViewportSize({ width, height: 600 });
+      await testctl.emit('JobsChanged', [LONG_JOB]);
+
+      // The indicator has to actually be up, or this test passes by
+      // measuring the idle case under another name.
+      await expect(app.locator('job-indicator')).toBeVisible();
+
+      await expect.poll(() => overflowingChildren(app)).toEqual([]);
+    });
+  }
+
+  /**
+   * The other half of "measured, never breakpointed": a rule that
+   * collapses defensively at every narrow width fits just as well and
+   * is a worse app. 1440 is roomy at any job title; 899 was measured to
+   * fit with the longest one, because `nav-history` is not there yet.
+   */
+  test('nothing is given up where there is room for it', async ({
+    app,
+    testctl,
+  }) => {
+    await app.setViewportSize({ width: 1440, height: 900 });
+    await testctl.emit('JobsChanged', [LONG_JOB]);
+    await expect(app.locator('job-indicator')).toBeVisible();
+
+    await expect.poll(() => collapsed(app)).toEqual({
+      wordmark: false,
+      jobLabel: false,
+    });
+  });
+
+  /**
+   * And it gives them back. The pass starts from all-visible every
+   * time, so this is the property that a rule which only ever *added*
+   * to the collapsed set would fail — the wordmark would be gone for
+   * the rest of the session after one narrow moment.
+   */
+  test('the wordmark comes back when the window does', async ({
+    app,
+    testctl,
+  }) => {
+    await testctl.emit('JobsChanged', [LONG_JOB]);
+    await app.setViewportSize({ width: 600, height: 600 });
+
+    await expect.poll(() => collapsed(app)).toEqual({
+      wordmark: true,
+      jobLabel: true,
+    });
+
+    await app.setViewportSize({ width: 1440, height: 900 });
+
+    await expect.poll(() => collapsed(app)).toEqual({
+      wordmark: false,
+      jobLabel: false,
+    });
+  });
+
+  /**
+   * The wordmark yields its width and not its existence: `display:
+   * none` would take the document from one top-level heading to none.
+   */
+  test('the collapsed wordmark is still the document heading', async ({
+    app,
+    testctl,
+  }) => {
+    await testctl.emit('JobsChanged', [LONG_JOB]);
+    await app.setViewportSize({ width: 600, height: 600 });
+
+    await expect.poll(() => collapsed(app)).toMatchObject({ wordmark: true });
+
+    await expect(
+      app.getByRole('heading', { name: 'YellowJacket', level: 1 }),
+    ).toHaveCount(1);
+  });
+
+  /**
+   * And the indicator keeps saying what it is doing after its visible
+   * label goes — the `sr-only` live region is what announces the state,
+   * which is the same argument the phone's own rule was written on.
+   */
+  test('the job indicator still announces its state without its label', async ({
+    app,
+    testctl,
+  }) => {
+    await testctl.emit('JobsChanged', [LONG_JOB]);
+    await app.setViewportSize({ width: 600, height: 600 });
+
+    await expect.poll(() => collapsed(app)).toMatchObject({ jobLabel: true });
+
+    const spoken = await app
+      .locator('job-indicator')
+      .evaluate(
+        (el) =>
+          el.shadowRoot?.querySelector('[aria-live]')?.textContent?.trim() ?? '',
+      );
+
+    expect(spoken).toContain('Scanning Music from the external drive');
+
+    // Leave the app as the next spec expects to find it.
+    await app.setViewportSize({ width: 1440, height: 900 });
+  });
+});

e2e/specs/view-lifecycle.spec.ts

@@ -4,6 +4,7 @@ import {
   eventNames,
   resetEvents,
   waitForEvent,
+  navigateTo,
 } from '../support/fixtures.js';
 
 /**
@@ -39,7 +40,9 @@ test.describe('view lifecycle', () => {
   test('a keypress on Settings does not reach the Autotag queue', async ({
     app,
   }) => {
-    await app.getByTestId('nav-autotag').click();
+    // By event, not by nav item: Autotag is hidden by default (#25)
+    // and a hidden view is still reachable.
+    await navigateTo(app, 'autotag');
     await expect(app.getByTestId('main-content')).toHaveAttribute(
       'data-active-view',
       'autotag',
@@ -83,7 +86,9 @@ test.describe('view lifecycle', () => {
     // The other half of the same bug (H-2): two document keydown handlers
     // with no arbitration meant `s` on this page skipped the album *and*
     // toggled shuffle.  As a panel binding it can only mean one thing.
-    await app.getByTestId('nav-autotag').click();
+    // By event, not by nav item: Autotag is hidden by default (#25)
+    // and a hidden view is still reachable.
+    await navigateTo(app, 'autotag');
     await expect
       .poll(() => pendingCount(app))
       .toMatch(/^Pending \(\d+\)$/);

e2e/specs/view-visibility.spec.ts

@@ -0,0 +1,116 @@
+import { test, expect, navigateTo } from '../support/fixtures.js';
+
+/**
+ * Which destinations the navigation offers (#25).
+ *
+ * Eleven sidebar entries is more than most libraries need, so they are
+ * individually toggleable from Settings, Autotag is off until asked for
+ * and Downloads is absent until there is a client to download with.
+ *
+ * **The assertions are about the navigation, not about the setting.**
+ * "The config was saved" is the plumbing, and the two most recent bugs
+ * in this area — #69 and #72 — both shipped green under specs that
+ * measured exactly that. What a person sees is whether the item is in
+ * the accessibility tree, and whether the view is still reachable when
+ * it is not.
+ *
+ * This runs against the seeded app, whose config is defaults and whose
+ * download client list is empty, so the initial state below is what a
+ * fresh install looks like.
+ */
+type Page = import('@playwright/test').Page;
+
+const navItem = (page: Page, label: string) =>
+  page.getByRole('button', { name: label, exact: true });
+
+/** The Navigation section's checkbox for a destination. */
+const viewToggle = (page: Page, label: string) =>
+  page.getByRole('checkbox', { name: `Show ${label} in the navigation` });
+
+async function openNavigationSettings(page: Page): Promise<void> {
+  await page.getByTestId('nav-settings').click();
+
+  const section = page.locator(
+    'config-page config-section[heading="Navigation"] .header',
+  );
+
+  await expect(section).toBeVisible();
+
+  if ((await section.getAttribute('aria-expanded')) === 'false') {
+    await section.click();
+  }
+
+  await expect(section).toHaveAttribute('aria-expanded', 'true');
+}
+
+test.describe('configurable destinations', () => {
+  test('Autotag is off by default and Downloads needs a client', async ({
+    app,
+  }) => {
+    await expect(app.getByTestId('nav-home')).toBeVisible();
+
+    await expect(app.getByTestId('nav-autotag')).toHaveCount(0);
+    await expect(app.getByTestId('nav-downloads')).toHaveCount(0);
+  });
+
+  /**
+   * Hiding takes the item away and nothing else. Detail views navigate
+   * into these and the launch page is one of them, so a destination
+   * with no nav item still has to open.
+   */
+  test('a hidden destination is still reachable', async ({ app }) => {
+    await navigateTo(app, 'autotag');
+
+    await expect(app.getByTestId('main-content')).toHaveAttribute(
+      'data-active-view',
+      'autotag',
+    );
+
+    // And nothing is falsely lit while standing on it -- the same rule
+    // a detail view follows, with no special case for either.
+    await expect(navItem(app, 'Home')).toHaveAttribute('aria-current', 'false');
+  });
+
+  test('switching Autotag on adds it to the sidebar', async ({ app }) => {
+    await openNavigationSettings(app);
+
+    await viewToggle(app, 'Autotag').check();
+
+    await expect(app.getByTestId('nav-autotag')).toBeVisible();
+
+    // Clicking it is the point of having it.
+    await app.getByTestId('nav-autotag').click();
+    await expect(app.getByTestId('main-content')).toHaveAttribute(
+      'data-active-view',
+      'autotag',
+    );
+
+    // Put it back, or the next spec against this app sees a library
+    // this one changed.
+    await openNavigationSettings(app);
+    await viewToggle(app, 'Autotag').uncheck();
+    await expect(app.getByTestId('nav-autotag')).toHaveCount(0);
+  });
+
+  /**
+   * Settings has no toggle at all, rather than a toggle that refuses:
+   * a user who hides it cannot get back to unhide it. The backend
+   * refuses it too, because `config.toml` is hand-editable.
+   */
+  test('Settings cannot be switched off', async ({ app }) => {
+    await openNavigationSettings(app);
+
+    await expect(viewToggle(app, 'Settings')).toBeDisabled();
+    await expect(app.getByTestId('nav-settings')).toBeVisible();
+  });
+
+  /**
+   * The launch page is refused while it is the launch page, which is a
+   * state the user can leave by changing the launch page above it.
+   */
+  test('the launch page cannot be switched off', async ({ app }) => {
+    await openNavigationSettings(app);
+
+    await expect(viewToggle(app, 'Home')).toBeDisabled();
+  });
+});

e2e/support/fixtures.ts

@@ -111,6 +111,35 @@ export async function bindingCalls(page: Page): Promise<string[]> {
   return calls.map(nameOf);
 }
 
+/**
+ * Go to a view without going through the navigation.
+ *
+ * `navigate` is the event the shell listens for and every nav item, card
+ * and detail view dispatches, so this is the app's own mechanism rather
+ * than a test-only door. It exists because a destination is not
+ * guaranteed to have a nav item any more (#25): Autotag is hidden until
+ * the user asks for it and Downloads until a client exists, and a spec
+ * about what a *view* does should not also be asserting that the
+ * sidebar offers it.
+ */
+export async function navigateTo(page: Page, view: string): Promise<void> {
+  await page.evaluate(
+    (v) =>
+      void document.dispatchEvent(
+        new CustomEvent('navigate', {
+          detail: { view: v },
+          bubbles: true,
+          composed: true,
+        }),
+      ),
+    view,
+  );
+
+  await page
+    .getByTestId('main-content')
+    .waitFor({ state: 'attached' });
+}
+
 /** Thin client for the dev-only /__test/ surface (backend/testctl). */
 export class TestCtl {
   constructor(private readonly baseURL: string) {}

frontend/bindings/yellowjacket/backend/config/config.ts

@@ -69,6 +69,14 @@ export function GetPinDefaultPlaylist(): $CancellablePromise<boolean> {
     return $Call.ByID(3818283301);
 }
 
+/**
+ * GetPopupVolume reports whether the bottom bar's volume control is a
+ * click-to-open popup rather than an inline slider (#42).
+ */
+export function GetPopupVolume(): $CancellablePromise<boolean> {
+    return $Call.ByID(2885777);
+}
+
 /**
  * GetQueueFallback returns what plays, if anything, once the queue
  * runs out.
@@ -112,6 +120,16 @@ export function GetTrackListColumns(): $CancellablePromise<tracklist$0.Column[]
     return $Call.ByID(3426289065);
 }
 
+/**
+ * GetViewVisibility reports which primary views the sidebar should
+ * show, answered for every known view rather than only the ones the
+ * config mentions -- so the frontend filters on a value and never has
+ * to hold a second copy of the defaults.
+ */
+export function GetViewVisibility(): $CancellablePromise<{ [_ in string]?: boolean } | null> {
+    return $Call.ByID(2798108026);
+}
+
 /**
  * Load reads and parses the config file from disk.
  */
@@ -197,6 +215,18 @@ export function SetPinDefaultPlaylist(pin: boolean): $CancellablePromise<void> {
     return $Call.ByID(372446849, pin);
 }
 
+/**
+ * SetPopupVolume saves the volume control's presentation.
+ * 
+ * Nothing to validate: both values are legal at every width, and the
+ * frontend additionally stands the inline slider down below the phone
+ * breakpoint whatever this says, because that is about room rather than
+ * about preference.
+ */
+export function SetPopupVolume(popup: boolean): $CancellablePromise<void> {
+    return $Call.ByID(1430308453, popup);
+}
+
 /**
  * SetQueueFallback validates and saves a new queue-fallback mode.
  */
@@ -247,6 +277,20 @@ export function SetTrackListColumns(columns: tracklist$0.Column[] | null): $Canc
     return $Call.ByID(4226159685, columns);
 }
 
+/**
+ * SetViewVisible shows or hides one primary view.
+ * 
+ * Two refusals, both about a state the user cannot get out of from the
+ * UI they would be left with: Settings is never hideable, and the
+ * launch page is never hideable while it is the launch page (change it
+ * first). Hiding a view does not make it unreachable -- `navigate`
+ * still resolves it, which detail views depend on -- it only takes the
+ * nav item away.
+ */
+export function SetViewVisible(view: string, visible: boolean): $CancellablePromise<void> {
+    return $Call.ByID(1751982648, view, visible);
+}
+
 /**
  * Validate returns errors if there is a breaking issue with the config.
  */

frontend/index.css

@@ -104,6 +104,42 @@ p {
     flex: 0 1 320px;
 }
 
+/* What the bar gives up when it does not fit is decided by measuring
+   it (`services/top-bar-fit.ts`, #143). Two rules here are what make
+   that measurement mean anything.
+
+   **Nothing but the search box may shrink.** `scrollWidth` reports a
+   perfect fit while a child quietly truncates -- #69's trap, one
+   component over -- and the indicator's label is `text-overflow:
+   ellipsis`, so it would have absorbed the deficit and hidden it. The
+   search box is exempt because it shrinks between its 320px basis and
+   the 200px floor its own stylesheet sets, and a narrower input hides
+   nothing it was showing. */
+.top-bar hgroup,
+.top-bar library-filter,
+.top-bar job-indicator {
+    flex-shrink: 0;
+}
+
+/* **The wordmark yields its width, not its existence.** It is the
+   app's top-level heading as well as its brand, and `display: none`
+   would take a document from one `h1` to none at exactly the widths
+   where the view's own header is the only thing left saying where you
+   are. This is `styles/sr-only.css.ts`'s recipe, written out because
+   that one is a `CSSResult` for shadow roots and this is the light
+   DOM. */
+.top-bar hgroup.yj-collapsed {
+    position: absolute;
+    width: 1px;
+    height: 1px;
+    padding: 0;
+    margin: -1px;
+    overflow: hidden;
+    clip-path: inset(50%);
+    white-space: nowrap;
+    border: 0;
+}
+
 /* The bar is `justify-content: space-between`, which with four children
    spreads them evenly and left back/forward floating in the middle of
    nothing. Collecting the free space *after* this one puts the pair
@@ -175,7 +211,39 @@ body div.sidebar {
     padding: 0.25em;
     background-color: var(--yj-bg-elevated, #343a40);
     display: grid;
-    grid-template-columns: var(--now-playing-width, 320px) 1fr auto;
+    /* Three columns whose outer two are the *same* width, which is what
+       centres the middle one (#23). It was `var(--now-playing-width) 1fr
+       auto`, so the transport's centre sat at `W/2 + 140px` — in the
+       middle of the space left over, which is not the same thing and
+       reads as an alignment mistake at every window size.
+
+       The outer width is still `--now-playing-width`, so **the metadata
+       panel's drag handle keeps meaning something**: widening it takes
+       room from the transport on both sides at once, symmetrically. An
+       `1fr … 1fr` pair would have centred the transport just as well and
+       silently made that handle a no-op.
+
+       **The cap is what stops that being a regression**, and it was
+       measured as one first. Reserving the full metadata width on both
+       sides costs the transport twice: at 800px the outer pair wanted
+       640 of 800, and the seek bar's track went from 257px to 61px
+       (and to 0 at 200% text) — the control you drag, squeezed out to
+       centre the buttons above it. So the side tracks are the metadata
+       width *or a quarter of the bar*, whichever is smaller, which
+       leaves the drag handle meaningful everywhere it has room to be
+       and hands the difference to the transport where it does not.
+
+       `minmax(0, …)` on the outer tracks and `min-content` on the middle
+       decide who yields when even that is not enough: the metadata and
+       the end group shrink (both truncate; neither loses an action), and
+       the transport keeps at least its buttons. Without the `min-content`
+       floor the middle collapses first, because a `1fr` track's minimum
+       is `auto` only until something else insists. */
+    --bar-side: min(var(--now-playing-width, 320px), 25%);
+    grid-template-columns:
+        minmax(0, var(--bar-side))
+        minmax(min-content, 1fr)
+        minmax(0, var(--bar-side));
     align-items: center;
     contain: layout style;
 
@@ -203,23 +271,44 @@ body div.sidebar {
             text-wrap-mode: nowrap;
             overflow: hidden;
 
-            p {
+            /* `& p`, not `p`. **A nested rule that begins with a bare
+               element selector is silently dropped before Chrome 120**
+               (relaxed nesting), and the phone this app runs on renders
+               in Chrome 113 -- so this ellipsis, and the two rules
+               below, have never applied on the device. Nothing fails;
+               the text simply overflows there. The `&` form is valid in
+               both, which is why it is used for every element selector
+               in this file's nested blocks. */
+            & p {
                 overflow: hidden;
                 text-overflow: ellipsis;
             }
         }
     }
 
-    now-playing {
+    & now-playing {
         overflow: hidden;
     }
 
-    audio-player {
+    & audio-player {
         margin: 0.5em 1em;
+        min-width: 0;
+    }
+
+    /* The right-hand group, and the thing the left column is matched
+       against. It is one grid cell rather than two columns because the
+       centring rule above compares *columns*: volume and the queue
+       button in separate tracks would make the outer pair unequal by
+       whatever the volume happens to measure. */
+    .bar-end {
+        justify-self: end;
+        display: flex;
+        align-items: center;
+        gap: 0.25em;
+        min-width: 0;
     }
 
     #queue-button {
-        justify-self: end;
         background: none;
         border: none;
         color: inherit;
@@ -404,6 +493,11 @@ body div.sidebar {
 }
 
 @media (max-width: 599px) {
+    /* The phone keeps the two-part bar it had: metadata, then the
+       transport and the queue button. There is no third column to
+       balance because the centring the desktop does is a luxury of
+       having room — at 360px the metadata needs all of the space the
+       controls do not. */
     .bottom-bar {
         grid-template-columns: minmax(0, 1fr) auto auto;
         gap: 0.25em;
@@ -412,4 +506,19 @@ body div.sidebar {
     .bottom-bar audio-player {
         margin: 0.25em;
     }
+
+    /* Volume stands down here whatever the setting says, because this
+       is about room and about the platform rather than about
+       preference: the hardware keys own volume on a phone, which is
+       also why mediacontrols' Android handler implements no volume
+       callback. It moved from `audio-player`'s own media query when
+       #42 moved the control into the bar — same rule, and now stated
+       where the element actually is.
+
+       `.bottom-bar volume-control`, not the one in
+       `now-playing-view`: that view is the phone's transport and is
+       where a slider does belong. */
+    .bottom-bar volume-control {
+        display: none;
+    }
 }

frontend/index.html

@@ -40,9 +40,23 @@
         </main>
         <queue-panel id="queue-panel"></queue-panel>
     </div>
+    <!-- Three columns, and the outer two are the same width, which is
+         what makes the middle one *centred* rather than merely in the
+         middle of what is left (#23). The transport used to sit in a
+         `320px 1fr auto` grid, so its centre was ~140px right of the
+         window's.
+
+         That is also why the volume moved out of `audio-player` and
+         into the bar (#42): the transport column has to contain the
+         transport and nothing else, or "centred" means centred with a
+         slider bolted to one side. It joins the queue button in
+         `.bar-end`, whose width is what the left column is matched
+         against. -->
     <footer class="bottom-bar">
         <now-playing></now-playing>
         <audio-player></audio-player>
+        <div class="bar-end">
+            <volume-control></volume-control>
             <button aria-label="Toggle queue" aria-controls="queue-panel" aria-expanded="false"
                 id="queue-button">
                 <!-- ICON_QUEUE in src/utils/icon-language.ts, written out
@@ -50,6 +64,7 @@
                      which is the Playlists destination's icon. -->
                 <wa-icon name="bars-staggered"></wa-icon>
             </button>
+        </div>
     </footer>
     <!-- The phone's primary navigation, hidden above 600px by
          index.css.  Eager rather than a chunk, for the reason

frontend/index.ts

@@ -18,6 +18,9 @@
 //   track-list — index.html renders one, so it is the first paint.
 // ---------------------------------------------------------------------------
 import '@components/audio-player/audio-player.ts';
+// In the bar rather than inside `audio-player` since #42, so the shell
+// is what has to register it.
+import '@components/audio-player/volume-control/volume-control.ts';
 import '@components/track-list/track-list.ts';
 import '@components/now-playing/now-playing.ts';
 import '@components/sidebar/app-sidebar.ts';
@@ -54,6 +57,7 @@ import '@store/theme-store';
 import './src/services/keyboard-shortcut-service';
 import { activateView, deactivateView } from '@utils/view-lifecycle';
 import { installLongPressContextMenu } from '@utils/long-press';
+import { installTopBarFit } from './src/services/top-bar-fit';
 import {
     hasTrackPayload,
     getDragPayload,
@@ -73,6 +77,14 @@ registerBundledIcons();
 // on `pointerType === 'touch'` only.
 installLongPressContextMenu();
 
+// The top bar decides what it can afford to show (#143). Here rather
+// than in a component because the bar is light DOM in index.html and
+// its children are five separate elements; the shell is the only thing
+// that can see all five at once.
+const topBar = document.querySelector<HTMLElement>('header.top-bar');
+
+if (topBar) installTopBarFit(topBar);
+
 // ---------------------------------------------------------------------------
 // View caching navigation system
 // ---------------------------------------------------------------------------
@@ -101,7 +113,6 @@ const VIEW_TAGS: Record<string, string> = {
     explore: 'explore-view',
     autotag: 'autotag-view',
     downloads: 'downloads-view',
-    jobs: 'jobs-view',
     settings: 'config-page',
 };
 
@@ -119,7 +130,6 @@ const VIEW_LOADERS: Record<string, () => Promise<unknown>> = {
     explore: () => import('@components/explore-view/explore-view.ts'),
     autotag: () => import('@components/autotag-view/autotag-view.ts'),
     downloads: () => import('@components/downloads-view/downloads-view.ts'),
-    jobs: () => import('@components/jobs/jobs-view.ts'),
     settings: () => import('@components/config-page/config-page.ts'),
 };
 

frontend/src/components/audio-player/audio-player.ts

@@ -3,7 +3,6 @@ import { customElement } from 'lit/decorators.js';
 import '@awesome.me/webawesome/dist/components/icon/icon.js';
 import './controls/player-controls';
 import './seekbar/seek-bar';
-import './volume-control/volume-control';
 import '../notifications/inline-notice';
 import { PlayerRegion } from '@store/player-store';
 import { designTokens } from '../../styles/tokens.css';
@@ -30,6 +29,7 @@ export class AudioPlayer extends LitElement {
 
     .player-main {
       flex: 1;
+      min-width: 0;
     }
 
     /* The phone transport (plan 016 B2): the buttons, and nothing
@@ -37,14 +37,17 @@ export class AudioPlayer extends LitElement {
        viewport, not by the host, so this is the component saying what
        it drops at phone width rather than the shell reaching in.
 
-       Volume goes because the hardware keys own it on a phone --
-       Android routes them to the media stream, which is also why
-       mediacontrols' Android handler implements no volume callback.
        The seek bar goes because a 4px-tall target dragged with a thumb
        is not a seek control; seeking belongs to the full-screen
-       now-playing view, which is the next phase. */
+       now-playing view.
+
+       Volume used to go from here too, and now goes from index.css
+       instead: #42 moved the control out of this component and into
+       the bar, so the shell is what can hide it. The reason is
+       unchanged -- the hardware keys own volume on a phone, which is
+       also why mediacontrols' Android handler implements no volume
+       callback. */
     @media (max-width: 599px) {
-      volume-control,
       seek-bar {
         display: none;
       }
@@ -65,7 +68,6 @@ export class AudioPlayer extends LitElement {
             <seek-bar></seek-bar>
           </div>
         </div>
-        <volume-control></volume-control>
       </div>
     `;
   }

frontend/src/components/audio-player/volume-control/volume-control.ts

@@ -4,6 +4,7 @@ import '@awesome.me/webawesome/dist/components/icon/icon.js';
 import '@awesome.me/webawesome/dist/components/slider/slider.js';
 import type WaSlider from '@awesome.me/webawesome/dist/components/slider/slider.js';
 import { PlayerController } from '@store/controllers/player-controller';
+import { volumeStyleStore } from '@store/volume-style-store';
 import { designTokens } from '../../../styles/tokens.css';
 import { waSliderLabel } from '../../../styles/wa-slider-label.css';
 
@@ -22,6 +23,12 @@ export class VolumeControl extends LitElement {
   @state()
   private showSlider = false;
 
+  /** Whether this is the click-to-open popup rather than a slider. */
+  @state()
+  private popup = volumeStyleStore.popup;
+
+  private unsubscribeStyle?: () => void;
+
   // Locally-tracked volume while the user is actively dragging or scrolling.
   // The store's volume only updates once the backend echoes VolumeChanged
   // (which we debounce), so we track intent here for responsive UI and to let
@@ -86,11 +93,31 @@ export class VolumeControl extends LitElement {
       --thumb-height: 16px;
     }
 
-    wa-slider::part(track) {
+    .volume-popup wa-slider::part(track) {
       background: var(--yj-text-primary, white);
       height: 120px;
     }
 
+    /* The inline slider (#42). It is the default now, so the width is
+       a real layout decision rather than a detail: 5em is wide enough
+       to aim at and narrow enough that the bottom bar's *outer*
+       columns stay equal without squeezing the transport — which is
+       the arrangement #23 depends on.
+
+       flex-shrink: 0 for the reason the top bar's children have it
+       (#143): a control that quietly gets narrower under pressure
+       hides the fact that the bar has run out of room. This one stands
+       down at phone width instead, in index.css, where the shell can
+       see the viewport. */
+    .inline-slider {
+      width: 5em;
+      flex-shrink: 0;
+    }
+
+    .inline-slider::part(track) {
+      background: var(--yj-text-primary, white);
+    }
+
     wa-slider::part(indicator) {
       background: var(--yj-accent, yellow);
     }
@@ -122,8 +149,23 @@ export class VolumeControl extends LitElement {
   // LIFECYCLE
   // ===================================================================
 
+  override connectedCallback() {
+    super.connectedCallback();
+
+    this.unsubscribeStyle = volumeStyleStore.subscribe(() => {
+      this.popup = volumeStyleStore.popup;
+
+      // Switching to the slider while the popup is open would leave the
+      // document listener installed for a popup that no longer renders.
+      if (!this.popup) this.closeSlider();
+    });
+
+    void volumeStyleStore.init();
+  }
+
   override disconnectedCallback() {
     super.disconnectedCallback();
+    this.unsubscribeStyle?.();
     document.removeEventListener('click', this.boundHandleOutsideClick);
     clearTimeout(this.volumeDebounceTimer);
   }
@@ -154,11 +196,13 @@ export class VolumeControl extends LitElement {
   private handleOutsideClick(e: Event) {
     const path = e.composedPath();
 
-    if (!path.includes(this)) {
+    if (!path.includes(this)) this.closeSlider();
+  }
+
+  private closeSlider() {
     this.showSlider = false;
     document.removeEventListener('click', this.boundHandleOutsideClick);
   }
-  }
 
   private handleInput(e: Event) {
     this.changeVolume((e.target as WaSlider).value);
@@ -192,18 +236,46 @@ export class VolumeControl extends LitElement {
   override render() {
     const muted = this.player.muted;
 
+    // Inline, the icon is the mute toggle rather than a disclosure:
+    // there is nothing left to disclose, and a button that opens a
+    // popup containing the slider already beside it would be a control
+    // whose only effect is to duplicate its neighbour.
+    const iconAction = this.popup
+      ? this.toggleSlider
+      : () => this.player.toggleMute();
+    const iconLabel = this.popup
+      ? muted
+        ? 'Muted'
+        : `Volume ${this.currentVolume}%`
+      : muted
+        ? 'Unmute'
+        : 'Mute';
+
     return html`
       <button
         class=${muted ? 'muted' : ''}
         title=${muted ? 'Muted — click for volume' : 'Volume'}
-        aria-label=${muted ? 'Muted' : `Volume ${this.currentVolume}%`}
+        aria-label=${iconLabel}
         data-muted=${muted ? 'true' : 'false'}
-        @click="${this.toggleSlider}"
+        @click="${iconAction}"
         @wheel="${this.handleWheel}"
       >
         <wa-icon name=${this.volumeIcon}></wa-icon>
       </button>
-      ${this.showSlider
+      ${!this.popup
+        ? html`
+            <wa-slider
+              class="inline-slider ${muted ? 'muted' : ''}"
+              label="Volume"
+              min="0"
+              max="100"
+              .value="${this.currentVolume}"
+              @input="${this.handleInput}"
+              @wheel="${this.handleWheel}"
+            ></wa-slider>
+          `
+        : ''}
+      ${this.popup && this.showSlider
         ? html`
             <div
               class="volume-popup ${muted ? 'muted' : ''}"

frontend/src/components/autotag-view/autotag-view.ts

@@ -29,6 +29,7 @@ import { nameDialogsIn } from '../../utils/name-dialog';
 import { ViewLifecycleMixin } from '../../utils/view-lifecycle';
 import { confirmAction } from '../confirm-dialog/confirm-dialog';
 import '@awesome.me/webawesome/dist/components/dialog/dialog.js';
+import '@components/jobs/job-panel';
 import { list } from '@utils/binding';
 
 type PendingItem = autotagservice.PendingItem;
@@ -135,8 +136,20 @@ export class AutotagView extends ViewLifecycleMixin(LitElement) {
                 padding: 0.75rem 1rem;
             }
 
-            .header {
+            /* The header and the apply-job panel share the header row.
+               A wrapper rather than a third grid row, because the panel
+               is display:none while nothing is applying and a grid
+               row would still spend the container's gap on it -- the
+               idle case, which is nearly always. */
+            .header-area {
                 grid-area: header;
+                display: flex;
+                flex-direction: column;
+                gap: 0.5rem;
+                min-width: 0;
+            }
+
+            .header {
                 display: flex;
                 align-items: center;
                 gap: 0.75rem;
@@ -3207,7 +3220,20 @@ export class AutotagView extends ViewLifecycleMixin(LitElement) {
         // sees a blank full-screen "Loading\u2026".
         return html`
             <div class="root">
+                <div class="header-area">
                     ${this.renderHeader()}
+                    <!--
+                      Applying rewrites tags on disk, and until #27 the
+                      only way to stop a run was the Jobs tab or the
+                      header popover. The per-album ring says work is
+                      happening; this is what can stop it, and what has
+                      the log when it goes wrong.
+                    -->
+                    <job-panel
+                        kinds="autotag-apply"
+                        heading="Applying tags"
+                    ></job-panel>
+                </div>
                 ${this.renderFolderSidebar()}
                 ${this.renderMain()}
             </div>

frontend/src/components/bottom-nav/bottom-nav.ts

@@ -8,6 +8,7 @@ import '../sidebar/app-sidebar.js';
 import { nameDialog } from '@utils/name-dialog';
 import { ICON_PLAYLIST } from '@utils/icon-language';
 import { ActiveViewController } from '@store/controllers/active-view-controller';
+import { ViewVisibilityController } from '@store/controllers/view-visibility-controller';
 
 type View = 'home' | 'albums' | 'tracks' | 'playlists';
 
@@ -129,6 +130,22 @@ export class BottomNav extends LitElement {
      */
     private activeCtrl = new ActiveViewController(this);
 
+    /**
+     * The tab bar honours the sidebar's toggles (#25), and the reason is
+     * inside this component rather than a general rule about phones.
+     * `PHONE_COLUMN_IDS` is the precedent for "what a phone shows is a
+     * different question", and it would apply here too -- except that
+     * "More" opens the *same* `<app-sidebar>`, which filters. An
+     * unfiltered bar would therefore contradict its own drawer, one tap
+     * apart, and a destination the user switched off is off wherever it
+     * is offered.
+     *
+     * Which four tabs remains plan 016's committed subset; this only
+     * removes from it. Hiding all four leaves "More", which is always
+     * present and reaches everything.
+     */
+    private visibilityCtrl = new ViewVisibilityController(this);
+
     /**
      * Whether the drawer has been asked for.
      *
@@ -211,7 +228,9 @@ export class BottomNav extends LitElement {
         return html`
             <nav aria-label="Primary">
                 <ul>
-                    ${BottomNav.TABS.map((tab) => html`
+                    ${BottomNav.TABS
+                        .filter((tab) => this.visibilityCtrl.visible(tab.id))
+                        .map((tab) => html`
                         <li>
                             <button
                                 type="button"

frontend/src/components/config-page/config-page.ts

@@ -9,7 +9,13 @@ import {
     RemoveLibrary,
     GetRemovalImpact,
     GetAllLibrariesWithTrackCounts,
+    ScanLibrary,
+    ScanAllLibraries,
+    FullRescan,
 } from '@go/library/library.js';
+import { jobStore } from '@store/job-store';
+import type { Job } from '@store/job-store';
+import '@components/jobs/job-panel';
 import {
     GetScanConcurrency,
     SetScanConcurrency,
@@ -19,6 +25,8 @@ import {
     SetQueueFallback,
     GetAllowMeteredCatalogDownload,
     SetAllowMeteredCatalogDownload,
+    GetPopupVolume,
+    SetPopupVolume,
 } from '@go/config/config.js';
 import { GetIndexStatus } from '@go/explore/service.js';
 import { notificationStore } from '@store/notification-store';
@@ -27,6 +35,9 @@ import type * as library from '@go/library/models.js';
 import { ThemeController } from '@store/controllers/theme-controller';
 import { TrackListController } from '@store/controllers/tracklist-controller';
 import { FavoritesController } from '@store/controllers/favorites-controller';
+import { ViewVisibilityController } from '@store/controllers/view-visibility-controller';
+import { VIEW_META } from '../../services/view-meta';
+import { downloadStore } from '@store/download-store';
 import { GetAllPlaylists } from '@go/playlist/service.js';
 import type * as playlist from '@go/playlist/models.js';
 import { Events } from '../../events';
@@ -71,6 +82,27 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
     // --- Favorites controller ---
     private favCtrl = new FavoritesController(this);
 
+    /** Which destinations the navigation offers (#25). */
+    private viewsCtrl = new ViewVisibilityController(this);
+
+    /**
+     * The job snapshot, for the per-library scan status (#27).
+     *
+     * Held as state rather than read from the store in `render()` so
+     * Lit sees the dependency: the store notifies, and a getter read
+     * inside a template is not a reactive input.
+     */
+    @state() private jobs: Job[] = [];
+
+    /**
+     * Set between pressing a scan button and the job snapshot that
+     * proves it started -- `JobsChanged` is coalesced at 250 ms, which
+     * is long enough for a second click to start a second scan.
+     */
+    @state() private startingScan = false;
+
+    private unsubscribeJobs: (() => void) | null = null;
+
     // --- Shortcuts controller ---
     private shortcutsCtrl = new ShortcutsController(this);
 
@@ -95,6 +127,8 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
     @state() private concurrencyMode = 'auto';
     @state() private defaultPage = 'home';
     @state() private queueFallback = 'favorites';
+
+    @state() private popupVolume = false;
     @state() private indexStatus: explore.IndexStatus | null = null;
     /** Three states, not one: the panel used to say "Loading status…"
      *  for the entire session, because the only thing that ever set
@@ -469,6 +503,12 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
             flex: 1;
         }
 
+        .view-note {
+            color: var(--yj-text-tertiary, #888);
+            font-size: var(--yj-font-size-sm, 0.85rem);
+            margin-left: auto;
+        }
+
         .column-arrows {
             display: flex;
             gap: 0.15em;
@@ -852,8 +892,14 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
         this.scrollMode =
             localStorage.getItem(SCROLL_STORAGE_KEY) || 'hover';
 
-        // Scan progress lives in the jobs panel now — this page only
-        // needs to know when the library list itself changes.
+        // Scanning is started and watched here (#27), so the job
+        // snapshot is a live input to this page.
+        this.unsubscribeJobs = jobStore.subscribe(() => {
+            this.jobs = jobStore.jobs;
+        });
+        this.jobs = jobStore.jobs;
+        void jobStore.init();
+
         this.cancelLibraryAdded = EventsOn(
             Events.LibraryAdded,
             () => void this.loadLibraries(),
@@ -884,6 +930,9 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
     }
 
     protected override onViewDeactivate(): void {
+        this.unsubscribeJobs?.();
+        this.unsubscribeJobs = null;
+
         this.cancelLibraryAdded?.();
         this.cancelLibraryRenamed?.();
         this.cancelLibraryRemoved?.();
@@ -893,13 +942,20 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
 
     private async loadLibraries(): Promise<void> {
         try {
-            const [libs, mode, defaultPage, queueFallback, allowMetered] =
-                await Promise.all([
+            const [
+                libs,
+                mode,
+                defaultPage,
+                queueFallback,
+                allowMetered,
+                popupVolume,
+            ] = await Promise.all([
                 GetAllLibrariesWithTrackCounts(),
                 GetScanConcurrency(),
                 GetDefaultPage(),
                 GetQueueFallback(),
                 GetAllowMeteredCatalogDownload(),
+                GetPopupVolume(),
             ]);
 
             this.libraries = libs ?? [];
@@ -907,6 +963,7 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
             this.defaultPage = defaultPage;
             this.queueFallback = queueFallback;
             this.allowMeteredCatalogDownload = allowMetered;
+            this.popupVolume = popupVolume;
 
         } catch (err) {
             console.error(
@@ -1084,6 +1141,133 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
         }
     }
 
+    // ===================================================================
+    // SCANNING (#27 — back from the Jobs tab)
+    // ===================================================================
+
+    /** The scan job for a library, if one is registered. */
+    private jobForLibrary(id: number): Job | undefined {
+        return this.jobs.find((job) => job.id === `scan:${id}`);
+    }
+
+    /** The status line under a library name while it is being scanned. */
+    private libraryScanStatus(id: number): string | null {
+        const job = this.jobForLibrary(id);
+
+        if (!job) return null;
+
+        switch (job.state) {
+            case 'running':
+                return job.phase ? `Scanning · ${job.phase}` : 'Scanning';
+            case 'queued':
+                return 'Queued';
+            case 'paused':
+                return 'Paused';
+            case 'pausing':
+                return 'Pausing…';
+            case 'cancelling':
+                return 'Stopping…';
+            default:
+                return null;
+        }
+    }
+
+    private get anyScanning(): boolean {
+        return this.libraries.some(
+            (lib) => this.libraryScanStatus(lib.id) !== null,
+        );
+    }
+
+    /**
+     * Run something that starts a job, holding the buttons until the
+     * snapshot lands and saying so when it does not start at all.
+     *
+     * Persistent, not a toast: the user asked for work to happen, it
+     * did not, and retrying is exactly the useful response.
+     */
+    private async startJob(
+        what: string,
+        start: () => Promise<unknown>,
+        retry: () => void,
+    ): Promise<void> {
+        if (this.startingScan) return;
+
+        this.startingScan = true;
+
+        try {
+            await start();
+        } catch (err) {
+            console.error(`${what} failed:`, err);
+            notificationStore.persistent({
+                key: 'scan-start',
+                title: 'Scan did not start',
+                text: `${what} failed. ${describeError(err)}`,
+                detail: String(err),
+                action: { label: 'Try again', run: retry },
+            });
+        } finally {
+            this.startingScan = false;
+        }
+    }
+
+    private handleScanLibrary = (id: number): void => {
+        this.activeMenuId = null;
+        void this.startJob(
+            'Scanning that library',
+            () => ScanLibrary(id),
+            () => this.handleScanLibrary(id),
+        );
+    };
+
+    private handleScanAll = (): void => {
+        void this.startJob(
+            'Scanning your libraries',
+            () => ScanAllLibraries(),
+            () => this.handleScanAll(),
+        );
+    };
+
+    private handleFullRescan = async (): Promise<void> => {
+        const ok = await confirmAction({
+            title: 'Full rescan',
+            message:
+                'This deletes all library data — including downloaded '
+                + 'cover art — and rebuilds it from your files.',
+            impact:
+                'It is not the same as “Scan now”, which only picks up '
+                + 'what changed.',
+            confirmLabel: 'Rebuild everything',
+            danger: true,
+        });
+
+        if (!ok) return;
+
+        await this.startJob(
+            'The full rescan',
+            () => FullRescan(),
+            () => void this.handleFullRescan(),
+        );
+    };
+
+    private handleViewToggle = (
+        view: string,
+        visible: boolean,
+    ): void => {
+        this.viewsCtrl
+            .setVisible(view, visible)
+            .catch((err: unknown) => {
+                console.error('Failed to save view visibility:', err);
+                notificationStore.transient({
+                    key: 'view-visibility',
+                    text: `Could not change which views are shown. ${describeError(err)}`,
+                    detail: String(err),
+                });
+                // The checkbox has already flipped itself; the store is
+                // the truth, so redraw from it.
+                this.requestUpdate();
+            });
+    };
+
     private handleDefaultPageChange = (
         e: CustomEvent<ConfigFieldChangeEvent>,
     ): void => {
@@ -1428,6 +1612,7 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
             -->
             ${this.renderLibrarySection()}
             ${this.renderGeneralSection()}
+            ${this.renderNavigationSection()}
             ${this.renderNowPlayingSection()}
             ${this.renderThemeSection()}
             ${this.renderTrackListSection()}
@@ -1522,6 +1707,20 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
                     .value=${this.allowMeteredCatalogDownload}
                     @config-change=${this.handleAllowMeteredChange}
                 ></config-field>
+
+                <!--
+                  The tier list above says what the build is *doing*;
+                  this says it is a job, and gives it the pause, cancel
+                  and log the tier list never had (#27). Cancelling one
+                  still asks first — that confirmation is inside
+                  applyJobControl, keyed on the kind, which is why
+                  this embeds the shared rows rather than drawing its
+                  own.
+                -->
+                <job-panel
+                    kinds="index-build,catalog-enrich"
+                    heading="Index jobs"
+                ></job-panel>
             </config-section>
         `;
     }
@@ -1642,18 +1841,15 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
                         description:
                             'The page the app opens to on launch.',
                         type: 'select' as const,
-                        options: [
-                            { value: 'home', label: 'Home' },
-                            { value: 'tracks', label: 'Tracks' },
-                            { value: 'albums', label: 'Albums' },
-                            { value: 'artists', label: 'Artists' },
-                            { value: 'genres', label: 'Genres' },
-                            { value: 'playlists', label: 'Playlists' },
-                            { value: 'explore', label: 'Explore' },
-                            { value: 'downloads', label: 'Downloads' },
-                            { value: 'autotag', label: 'Autotag' },
-                            { value: 'jobs', label: 'Jobs' },
-                        ],
+                        // Derived, not written out: this list was a
+                        // second copy of the launchable set, and #27
+                        // removing a destination is exactly the change
+                        // that would have left the two disagreeing.
+                        // Settings is excluded because it is the one
+                        // view the backend refuses to launch into.
+                        options: VIEW_META
+                            .filter((v) => v.alwaysShown !== true)
+                            .map((v) => ({ value: v.id, label: v.label })),
                     }}
                     .value=${this.defaultPage}
                     @config-change=${this.handleDefaultPageChange}
@@ -1674,6 +1870,120 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
                     .value=${this.queueFallback}
                     @config-change=${this.handleQueueFallbackChange}
                 ></config-field>
+                <config-field
+                    .schema=${{
+                        key: 'popupVolume',
+                        label: 'Volume opens in a popup',
+                        description:
+                            'Off, the volume slider is always visible in the '
+                            + 'player bar. On, it hides behind the speaker '
+                            + 'icon. The slider stands down on a phone either '
+                            + 'way, where the hardware keys own volume.',
+                        type: 'toggle' as const,
+                    }}
+                    .value=${this.popupVolume}
+                    @config-change=${this.handlePopupVolumeChange}
+                ></config-field>
+            </config-section>
+        `;
+    }
+
+    /**
+     * The volume control's presentation (#42).
+     *
+     * In General rather than beside the theme because it is about the
+     * transport's behaviour rather than its colours, and next to "When
+     * the Queue Ends" because both are answers to "how should the
+     * player behave".
+     */
+    private handlePopupVolumeChange = (
+        e: CustomEvent<ConfigFieldChangeEvent>,
+    ): void => {
+        const popup = Boolean(e.detail.value);
+        const previous = this.popupVolume;
+
+        this.popupVolume = popup;
+
+        void SetPopupVolume(popup).catch((err: unknown) => {
+            console.error('failed to save the volume control setting', err);
+            this.popupVolume = previous;
+            notificationStore.transient({
+                key: 'popup-volume-setting',
+                title: 'Setting not saved',
+                text: describeError(err, 'That setting could not be saved.'),
+            });
+        });
+    };
+
+    // --- Navigation section ---
+
+    /**
+     * Which destinations the sidebar and the phone's tab bar offer.
+     *
+     * Two items are drawn but not editable, and both say why in place
+     * rather than being silently inert. Settings is never hideable --
+     * the backend refuses it too, because `config.toml` is
+     * hand-editable. The launch page is not hideable *while it is the
+     * launch page*, which is a state the user can leave by changing the
+     * launch page above; refusing is preferable to the alternatives,
+     * since resetting their launch page silently changes a second thing
+     * they chose and allowing it lands the app on a page nothing points
+     * at.
+     */
+    private renderNavigationSection() {
+        return html`
+            <config-section
+                heading="Navigation"
+                description="Choose which destinations the sidebar and the phone's tab bar offer. Hiding one does not remove it — links and the launch page still open it."
+            >
+                <ul class="column-list">
+                    ${repeat(VIEW_META, (v) => v.id, (v) => {
+            const checked = this.viewsCtrl.enabled(v.id);
+            const isLaunchPage = this.defaultPage === v.id;
+            const locked = v.alwaysShown === true || isLaunchPage;
+
+            let note = '';
+
+            if (v.alwaysShown === true) {
+                note = 'Always shown.';
+            } else if (isLaunchPage) {
+                note = 'This is the launch page.';
+            } else if (
+                v.id === 'downloads' &&
+                checked &&
+                !downloadStore.available
+            ) {
+                // The config says show it and the nav does not, which
+                // would otherwise read as the checkbox not working.
+                note = 'Hidden until a download client is configured.';
+            }
+
+            return html`
+                            <li
+                                class="column-item ${checked ? 'enabled' : 'disabled'}"
+                            >
+                                <input
+                                    type="checkbox"
+                                    class="column-toggle"
+                                    aria-label="Show ${v.label} in the navigation"
+                                    .checked=${checked}
+                                    ?disabled=${locked}
+                                    @change=${(e: Event) =>
+                    this.handleViewToggle(
+                        v.id,
+                        (e.target as HTMLInputElement).checked,
+                    )}
+                                />
+                                <span class="column-label">
+                                    ${v.label}
+                                </span>
+                                ${note
+                    ? html`<span class="view-note">${note}</span>`
+                    : nothing}
+                            </li>
+                        `;
+        })}
+                </ul>
             </config-section>
         `;
     }
@@ -2056,8 +2366,8 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
         return html`
             <config-section
                 heading="Libraries"
-                description="Manage your music library folders. Scanning and its
-                    progress live in the Jobs panel."
+                description="Manage your music library folders, and scan them
+                    for new and changed files."
                 .open=${true}
             >
                 <div class="scan-actions">
@@ -2067,6 +2377,23 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
                     >
                         Add Library
                     </button>
+                    <button
+                        ?disabled=${this.anyScanning
+                || this.startingScan
+                || this.libraries.length === 0}
+                        @click=${this.handleScanAll}
+                    >
+                        Scan All
+                    </button>
+                    <button
+                        class="btn-danger"
+                        ?disabled=${this.anyScanning
+                || this.startingScan
+                || this.libraries.length === 0}
+                        @click=${this.handleFullRescan}
+                    >
+                        Full Rescan
+                    </button>
                 </div>
 
                 ${this.libraries.length > 0
@@ -2104,7 +2431,8 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
                                         <span class="library-count">
                                             ${this.removingLibraryId === lib.id
                                                 ? 'Removing…'
-                                                : html`${lib.trackCount} tracks`}
+                                                : this.libraryScanStatus(lib.id)
+                                                    ?? html`${lib.trackCount} tracks`}
                                         </span>
                                         <div class="overflow-wrapper">
                                             <button
@@ -2127,6 +2455,16 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
                                                           >
                                                               Rename
                                                           </div>
+                                                          ${this.libraryScanStatus(lib.id) === null
+                                                            ? html`
+                                                                  <div
+                                                                      class="overflow-item"
+                                                                      @click=${() => this.handleScanLibrary(lib.id)}
+                                                                  >
+                                                                      Scan now
+                                                                  </div>
+                                                              `
+                                                            : nothing}
                                                           <div
                                                               class="overflow-item overflow-item--danger"
                                                               @click=${() => void this.handleRemoveClick(lib.id)}
@@ -2170,6 +2508,11 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
                     @config-change=${this.handleConcurrencyChange}
                 ></config-field>
 
+                <job-panel
+                    kinds="library-scan"
+                    heading="Scans"
+                ></job-panel>
+
             </config-section>
         `;
     }

frontend/src/components/config-page/download-clients.ts

@@ -22,6 +22,7 @@ import { compact } from '@utils/binding';
 import { describeError, explainError } from '@utils/describe-error';
 import { confirmAction } from '@components/confirm-dialog/confirm-dialog';
 import './config-section';
+import '@components/jobs/job-panel';
 import { pickDirectory } from '../../utils/pick-directory';
 
 /**
@@ -274,6 +275,17 @@ export class DownloadClients extends LitElement {
                             </wa-button>
                         </div>
                     `}
+
+                <!--
+                  The Downloads view already shows every download's
+                  lifecycle state; what it has never had is pause,
+                  cancel and the log, which the Jobs tab carried (#27).
+                  Renders nothing while nothing is downloading.
+                -->
+                <job-panel
+                    kinds="download"
+                    heading="Downloads in progress"
+                ></job-panel>
             </config-section>
 
             <config-section

frontend/src/components/download-picker/download-picker.ts

@@ -246,7 +246,7 @@ export class DownloadPicker extends LitElement {
             return html`
                 <wa-callout variant="success">
                     Found a clear match and started downloading it. Progress is
-                    in the background jobs panel.
+                    on the Downloads page.
                 </wa-callout>
             `;
         }

frontend/src/components/jobs/job-indicator.ts

@@ -155,13 +155,27 @@ export class JobIndicator extends LitElement {
                goes -- the live region in render() is what announces
                this, and it is unaffected, so the ring keeps its
                accessible name and screen readers keep hearing the
-               state change. */
+               state change.
+
+               [compact] is the same removal asked for by measurement
+               rather than by width, and it is set from outside: the
+               shell's fit pass (services/top-bar-fit.ts, #143) owns
+               it, because between 600 and 900 whether this label fits
+               depends on what else is in the bar and on how long the
+               running job's title is -- 235px for "Scanning Music from
+               the external drive" -- rather than on the viewport. Two
+               triggers, one effect, and the phone's is unconditional
+               because it was argued and pinned before this existed. */
             @media (max-width: 599px) {
                 .label {
                     display: none;
                 }
             }
 
+            :host([compact]) .label {
+                display: none;
+            }
+
             .alert-dot {
                 width: 6px;
                 height: 6px;

frontend/src/components/jobs/job-panel.ts

@@ -0,0 +1,229 @@
+import { LitElement, html, css, nothing } from 'lit';
+import { customElement, property, state } from 'lit/decorators.js';
+import { designTokens } from '../../styles/tokens.css';
+import { jobStore } from '@store/job-store';
+import type { Job, JobKind } from '@store/job-store';
+import { isTerminal } from '@store/job-store';
+import './job-row';
+import './job-details-drawer';
+import { applyJobControl } from './job-controls';
+import { jobStateStyles } from './job-format';
+
+/**
+ * The background work of one kind, rendered wherever that work is
+ * started or configured.
+ *
+ * #27 folded the Jobs tab away, and the shape it folded into is this
+ * rather than one "Background jobs" panel in Settings — which would
+ * have been the tab again under another name. Reading the app first
+ * turned up that **four of the five job kinds already had a home**
+ * showing their work: Settings → Search Index draws per-tier index
+ * progress, `downloads-view` draws every download's lifecycle state,
+ * `autotag-view` draws its own apply ring, and only `library-scan` had
+ * nowhere but the tab. What none of those four had is the *generic*
+ * affordances — pause, cancel, "Details", the log, and a finished job
+ * you can dismiss — which is what this carries to each of them.
+ *
+ * Three things about it are load-bearing.
+ *
+ * **The controls are `applyJobControl`, not a reimplementation.** That
+ * is what keeps the "you will discard hours of downloading"
+ * confirmation on an index build alive across the move: it is keyed on
+ * `KindIndexBuild` inside the shared handler, and a host that rendered
+ * its own buttons would silently drop it.
+ *
+ * **A panel with nothing to say renders nothing at all**, host padding
+ * included — an idle panel in four places is four pieces of furniture
+ * describing an absence. That is the rule `startBackfillJob` follows
+ * for the indicator, one layer up.
+ *
+ * **There is no "Clear finished" here**, because `ClearFinishedJobs` is
+ * global: a Clear in the Libraries panel would silently discard the
+ * index build's history too. A finished row dismisses itself, which is
+ * per-job and is what `job-row` already offers.
+ */
+@customElement('job-panel')
+export class JobPanel extends LitElement {
+    /**
+     * Comma-separated job kinds, e.g. `index-build,catalog-enrich`.
+     *
+     * An attribute rather than a property because every call site is a
+     * literal in a template, and one of them is inside an HTMX-adjacent
+     * settings page where a property binding would be one more thing to
+     * remember.
+     */
+    @property({ type: String })
+    kinds = '';
+
+    /** Heading above the rows. Omitted renders no heading. */
+    @property({ type: String })
+    heading = '';
+
+    @state()
+    private jobs: Job[] = [];
+
+    @state()
+    private drawerJobId = '';
+
+    @state()
+    private drawerOpen = false;
+
+    private unsubscribe: (() => void) | null = null;
+
+    static override styles = [
+        designTokens,
+        jobStateStyles,
+        css`
+            :host {
+                display: block;
+                margin-top: 1em;
+            }
+
+            /* An empty panel takes no room at all, margin included. */
+            :host([hidden]) {
+                display: none;
+            }
+
+            h3 {
+                font-size: var(--yj-text-sm);
+                text-transform: uppercase;
+                letter-spacing: 0.06em;
+                color: var(--yj-text-tertiary, #868e96);
+                margin: 0 0 0.5em;
+            }
+
+            .card {
+                background: var(--yj-bg-surface, #2b3035);
+                border: 1px solid var(--yj-border, #495057);
+                border-radius: 6px;
+                overflow: hidden;
+            }
+
+            .job-entry {
+                display: flex;
+                align-items: center;
+                gap: 0.75em;
+                padding: 0.6em 0.8em;
+                border-bottom: 1px solid var(--yj-border-subtle, #3a4046);
+            }
+
+            .job-entry:last-child {
+                border-bottom: none;
+            }
+
+            job-row {
+                flex: 1;
+                /* A grid child's implicit minimum is its content, and a
+                   job title is long. */
+                min-width: 0;
+            }
+
+            .details-btn {
+                background: none;
+                border: 1px solid var(--yj-border, #495057);
+                border-radius: 4px;
+                color: var(--yj-text-secondary, #adb5bd);
+                cursor: pointer;
+                font-family: inherit;
+                font-size: var(--yj-text-sm);
+                padding: 0.3em 0.6em;
+                white-space: nowrap;
+            }
+
+            .details-btn:hover {
+                color: var(--yj-text-primary, #e9ecef);
+            }
+        `,
+    ];
+
+    override connectedCallback() {
+        super.connectedCallback();
+        this.unsubscribe = jobStore.subscribe(() => {
+            this.jobs = jobStore.jobs;
+        });
+        this.jobs = jobStore.jobs;
+        void jobStore.init();
+    }
+
+    override disconnectedCallback() {
+        super.disconnectedCallback();
+        this.unsubscribe?.();
+        this.unsubscribe = null;
+    }
+
+    /** The kinds this panel answers for. */
+    private get wanted(): ReadonlySet<string> {
+        return new Set(
+            this.kinds
+                .split(',')
+                .map((k) => k.trim())
+                .filter(Boolean),
+        );
+    }
+
+    private get mine(): Job[] {
+        const wanted = this.wanted;
+
+        return this.jobs.filter((job) => wanted.has(job.kind as JobKind));
+    }
+
+    private openDetails(id: string) {
+        this.drawerJobId = id;
+        this.drawerOpen = true;
+    }
+
+    private onDrawerClosed = () => {
+        this.drawerOpen = false;
+    };
+
+    override render() {
+        const mine = this.mine;
+
+        // Hidden rather than empty: see the class comment. The drawer
+        // goes with it, since it can only have been opened from a row.
+        this.hidden = mine.length === 0;
+
+        if (mine.length === 0) return nothing;
+
+        const active = mine.filter((job) => !isTerminal(job));
+        const finished = mine.filter(isTerminal);
+
+        return html`
+            ${this.heading ? html`<h3>${this.heading}</h3>` : nothing}
+            <div class="card">
+                ${[...active, ...finished].map(
+                    (job) => html`
+                        <div class="job-entry">
+                            <job-row
+                                .job=${job}
+                                variant="full"
+                                @job-control=${applyJobControl}
+                            ></job-row>
+                            <button
+                                type="button"
+                                class="details-btn"
+                                @click=${() => this.openDetails(job.id)}
+                            >
+                                Details${job.warnCount
+                                    ? ` · ${job.warnCount}⚠`
+                                    : ''}
+                            </button>
+                        </div>
+                    `,
+                )}
+            </div>
+
+            <job-details-drawer
+                job-id=${this.drawerJobId}
+                ?open=${this.drawerOpen}
+                @drawer-closed=${this.onDrawerClosed}
+            ></job-details-drawer>
+        `;
+    }
+}
+
+declare global {
+    interface HTMLElementTagNameMap {
+        'job-panel': JobPanel;
+    }
+}

frontend/src/components/jobs/jobs-view.ts

@@ -1,568 +0,0 @@
-import { LitElement, html, css, nothing } from 'lit';
-import { customElement, state } from 'lit/decorators.js';
-import '@awesome.me/webawesome/dist/components/icon/icon.js';
-import '@components/page-header/page-header';
-import { designTokens } from '../../styles/tokens.css';
-import {
-    GetAllLibrariesWithTrackCounts,
-    ScanLibrary,
-    ScanAllLibraries,
-    FullRescan,
-} from '@go/library/library.js';
-import type * as library from '@go/library/models.js';
-import { EventsOn } from '@runtime/runtime';
-import { Events } from '../../events';
-import { jobStore } from '@store/job-store';
-import type { Job } from '@store/job-store';
-import { notificationStore } from '@store/notification-store';
-import { describeError } from '@utils/describe-error';
-import { confirmAction } from '../confirm-dialog/confirm-dialog';
-import './job-row';
-import './job-details-drawer';
-import { applyJobControl } from './job-controls';
-import { jobStateStyles } from './job-format';
-import { ViewLifecycleMixin } from '../../utils/view-lifecycle';
-
-type LibraryInfo = library.Info;
-
-/** Job states meaning the job will not progress further. */
-const TERMINAL_STATES: ReadonlySet<string> = new Set([
-    'complete',
-    'cancelled',
-    'error',
-]);
-
-/**
- * Full-page view of background work: everything running right now, the
- * per-library scan controls that used to live in Settings, and a short
- * history of what recently finished.
- *
- * This is the same job rows as the top-bar popover at a larger density —
- * one implementation, two placements, so the two can never disagree.
- */
-@customElement('jobs-view')
-export class JobsView extends ViewLifecycleMixin(LitElement) {
-    @state()
-    private jobs: Job[] = [];
-
-    @state()
-    private libraries: LibraryInfo[] = [];
-
-    @state()
-    private drawerJobId = '';
-
-    @state()
-    private drawerOpen = false;
-
-    /**
-     * Set between pressing a scan button and the job snapshot that
-     * proves it started. `anyScanning` is derived from `JobsChanged`,
-     * which is coalesced at 250 ms — long enough for a second click to
-     * start a second scan (errors.M5).
-     */
-    @state()
-    private starting = false;
-
-    private unsubscribe: (() => void) | null = null;
-
-    private eventCleanups: Array<() => void> = [];
-
-    static override styles = [
-        designTokens,
-        jobStateStyles,
-        css`
-            :host {
-                display: block;
-                overflow-y: auto;
-                height: 100%;
-                padding: 1.5em 1.75em 3em;
-                box-sizing: border-box;
-            }
-
-            /* The header supplies its own padding and rule, so it runs
-               to the edge of a host that pads its own content. */
-            page-header {
-                margin: -1.5em -1.75em 1em;
-            }
-
-            h1 {
-                font-size: var(--yj-text-xl);
-                color: var(--yj-text-primary, #e9ecef);
-                margin: 0 0 0.2em;
-            }
-
-            .page-sub {
-                font-size: var(--yj-text-md);
-                color: var(--yj-text-tertiary, #868e96);
-                margin: 0 0 1.75em;
-            }
-
-            section {
-                margin-bottom: 2em;
-            }
-
-            .section-head {
-                display: flex;
-                align-items: center;
-                justify-content: space-between;
-                gap: 1em;
-                margin-bottom: 0.75em;
-            }
-
-            h2 {
-                font-size: var(--yj-text-sm);
-                text-transform: uppercase;
-                letter-spacing: 0.06em;
-                color: var(--yj-text-tertiary, #868e96);
-                margin: 0;
-            }
-
-            .card {
-                background: rgba(255, 255, 255, 0.03);
-                border: 1px solid rgba(255, 255, 255, 0.07);
-                border-radius: 10px;
-                overflow: hidden;
-            }
-
-            .card > * + * {
-                border-top: 1px solid rgba(255, 255, 255, 0.06);
-            }
-
-            .job-entry {
-                display: grid;
-                grid-template-columns: 1fr auto;
-                align-items: center;
-                gap: 0.5em;
-                padding-right: 0.75em;
-            }
-
-            .empty {
-                padding: 1.1em;
-                font-size: var(--yj-text-md);
-                color: var(--yj-text-tertiary, #868e96);
-                font-style: italic;
-            }
-
-            .library-row {
-                display: grid;
-                grid-template-columns: 1fr auto;
-                align-items: center;
-                gap: 1em;
-                padding: 0.75em 0.9em;
-            }
-
-            .library-name {
-                font-size: var(--yj-text-md);
-                color: var(--yj-text-primary, #e9ecef);
-            }
-
-            .library-meta {
-                font-size: var(--yj-text-sm);
-                color: var(--yj-text-tertiary, #868e96);
-                margin-top: 0.15em;
-                overflow-wrap: anywhere;
-            }
-
-            .library-state {
-                font-size: var(--yj-text-sm);
-                color: var(--job-tone);
-                margin-top: 0.15em;
-            }
-
-            button.action {
-                display: inline-flex;
-                align-items: center;
-                gap: 0.45em;
-                border: 1px solid rgba(255, 255, 255, 0.14);
-                border-radius: 7px;
-                background: rgba(255, 255, 255, 0.05);
-                color: var(--yj-text-primary, #e9ecef);
-                font-size: var(--yj-text-sm);
-                padding: 0.42em 0.85em;
-                cursor: pointer;
-                white-space: nowrap;
-                transition:
-                    background-color 120ms ease,
-                    border-color 120ms ease;
-            }
-
-            button.action:hover:not(:disabled) {
-                background: rgba(255, 255, 255, 0.11);
-            }
-
-            button.action:disabled {
-                opacity: 0.4;
-                cursor: default;
-            }
-
-            button.action:focus-visible {
-                outline: 2px solid var(--yj-accent, #ffd43b);
-                outline-offset: 2px;
-            }
-
-            button.action.danger {
-                color: var(--yj-error-text, #ff8787);
-                border-color: rgba(255, 107, 107, 0.35);
-            }
-
-            button.action.danger:hover:not(:disabled) {
-                background: rgba(255, 107, 107, 0.12);
-            }
-
-            button.link {
-                border: none;
-                background: transparent;
-                color: var(--yj-accent-text, #ffd43b);
-                font-size: var(--yj-text-sm);
-                cursor: pointer;
-                padding: 0.2em 0.4em;
-                border-radius: 5px;
-            }
-
-            button.link:hover {
-                text-decoration: underline;
-            }
-
-            .details-btn {
-                border: none;
-                background: transparent;
-                color: var(--yj-text-secondary, #adb5bd);
-                font-size: var(--yj-text-sm);
-                cursor: pointer;
-                padding: 0.3em 0.5em;
-                border-radius: 6px;
-                white-space: nowrap;
-            }
-
-            .details-btn:hover {
-                background: rgba(255, 255, 255, 0.1);
-                color: var(--yj-text-primary, #e9ecef);
-            }
-        `,
-    ];
-
-    protected override onViewActivate(): void {
-        this.unsubscribe = jobStore.subscribe(() => {
-            this.jobs = jobStore.jobs;
-        });
-        void jobStore.init();
-        this.jobs = jobStore.jobs;
-        void this.loadLibraries();
-
-        // Library CRUD happens elsewhere; keep the picker in step.
-        for (const event of [
-            Events.LibraryAdded,
-            Events.LibraryRemoved,
-            Events.LibraryRenamed,
-            Events.LibraryScanComplete,
-        ]) {
-            this.eventCleanups.push(
-                EventsOn(event, () => void this.loadLibraries()),
-            );
-        }
-    }
-
-    protected override onViewDeactivate(): void {
-        this.unsubscribe?.();
-        this.unsubscribe = null;
-        this.eventCleanups.forEach((off) => off());
-        this.eventCleanups = [];
-    }
-
-    private async loadLibraries(): Promise<void> {
-        try {
-            this.libraries = (await GetAllLibrariesWithTrackCounts()) ?? [];
-        } catch (err) {
-            console.error('Failed to load libraries:', err);
-        }
-    }
-
-    /** The scan job for a library, if one is registered. */
-    private jobForLibrary(id: number): Job | undefined {
-        return jobStore.getJob(`scan:${id}`);
-    }
-
-    private openDetails(id: string) {
-        this.drawerJobId = id;
-        this.drawerOpen = true;
-    }
-
-    private onDrawerClosed = () => {
-        this.drawerOpen = false;
-    };
-
-    /**
-     * Run something that starts a job, holding the buttons until the
-     * snapshot lands and saying so when it does not start at all.
-     *
-     * Persistent, not a toast: the user asked for work to happen, it
-     * did not, and retrying is exactly the useful response.
-     */
-    private async startJob(
-        what: string,
-        start: () => Promise<unknown>,
-        retry: () => void,
-    ): Promise<void> {
-        if (this.starting) return;
-
-        this.starting = true;
-
-        try {
-            await start();
-        } catch (err) {
-            console.error(`${what} failed:`, err);
-            notificationStore.persistent({
-                key: 'scan-start',
-                title: 'Scan did not start',
-                text: `${what} failed. ${describeError(err)}`,
-                detail: String(err),
-                action: { label: 'Try again', run: retry },
-            });
-        } finally {
-            this.starting = false;
-        }
-    }
-
-    private async startScan(id: number) {
-        await this.startJob(
-            'Scanning that library',
-            () => ScanLibrary(id),
-            () => void this.startScan(id),
-        );
-    }
-
-    private async startAllScans() {
-        await this.startJob(
-            'Scanning your libraries',
-            () => ScanAllLibraries(),
-            () => void this.startAllScans(),
-        );
-    }
-
-    private async clearFinished() {
-        await jobStore.clearFinished();
-    }
-
-    private async fullRescan() {
-        const ok = await confirmAction({
-            title: 'Full rescan',
-            message:
-                'This deletes all library data — including downloaded ' +
-                'cover art — and rebuilds it from your files.',
-            impact:
-                'It is not the same as “Scan now”, which only picks up ' +
-                'what changed.',
-            confirmLabel: 'Rebuild everything',
-            danger: true,
-        });
-
-        if (!ok) return;
-
-        await this.startJob(
-            'The full rescan',
-            () => FullRescan(),
-            () => void this.fullRescan(),
-        );
-    }
-
-    private renderJobList(list: Job[], emptyText: string) {
-        if (list.length === 0) {
-            return html`<div class="card">
-                <div class="empty">${emptyText}</div>
-            </div>`;
-        }
-
-        return html`
-            <div class="card">
-                ${list.map(
-                    (job) => html`
-                        <div class="job-entry">
-                            <job-row
-                                .job=${job}
-                                variant="full"
-                                @job-control=${applyJobControl}
-                            ></job-row>
-                            <button
-                                class="details-btn"
-                                @click=${() => this.openDetails(job.id)}
-                            >
-                                Details${job.warnCount
-                                    ? ` · ${job.warnCount}⚠`
-                                    : ''}
-                            </button>
-                        </div>
-                    `,
-                )}
-            </div>
-        `;
-    }
-
-    /** The status line under a library name in the scan-control list. */
-    private libraryStatus(job: Job | undefined): string | null {
-        if (!job) return null;
-
-        switch (job.state) {
-            case 'running':
-                return job.phase ? `Scanning · ${job.phase}` : 'Scanning';
-            case 'queued':
-                return 'Queued';
-            case 'paused':
-                return 'Paused';
-            case 'pausing':
-                return 'Pausing…';
-            case 'cancelling':
-                return 'Stopping…';
-            default:
-                return null;
-        }
-    }
-
-    private renderLibraryRow(lib: LibraryInfo) {
-        const job = this.jobForLibrary(lib.id);
-        const status = this.libraryStatus(job);
-        const busy = status !== null;
-
-        return html`
-            <div class="library-row">
-                <div>
-                    <div class="library-name">${lib.name}</div>
-                    <div class="library-meta">
-                        ${lib.trackCount.toLocaleString()} tracks · ${lib.path}
-                    </div>
-                    ${status
-                        ? html`<div class="library-state">${status}</div>`
-                        : nothing}
-                </div>
-
-                ${busy
-                    ? html`
-                          <button
-                              class="link"
-                              @click=${() => this.openDetails(`scan:${lib.id}`)}
-                          >
-                              View progress
-                          </button>
-                      `
-                    : html`
-                          <button
-                              class="action"
-                              ?disabled=${this.starting}
-                              @click=${() => this.startScan(lib.id)}
-                          >
-                              <wa-icon name="arrows-rotate"></wa-icon>
-                              Scan now
-                          </button>
-                      `}
-            </div>
-        `;
-    }
-
-    override render() {
-        // Derived from `this.jobs` rather than the store getters so Lit
-        // sees the reactive dependency and re-renders on every snapshot.
-        const active = this.jobs.filter((j) => !TERMINAL_STATES.has(j.state));
-        const finished = this.jobs.filter((j) => TERMINAL_STATES.has(j.state));
-        const anyScanning = this.libraries.some((lib) =>
-            Boolean(this.libraryStatus(this.jobForLibrary(lib.id))),
-        );
-
-        return html`
-            <page-header heading="Background jobs"></page-header>
-            <p class="page-sub">
-                Library scans and search index builds, with their progress and
-                output.
-            </p>
-
-            <section>
-                <div class="section-head">
-                    <h2>Running now</h2>
-                </div>
-                ${this.renderJobList(active, 'Nothing is running.')}
-            </section>
-
-            <section>
-                <div class="section-head">
-                    <h2>Libraries</h2>
-                    <button
-                        class="action"
-                        ?disabled=${anyScanning ||
-                        this.starting ||
-                        this.libraries.length === 0}
-                        @click=${this.startAllScans}
-                    >
-                        <wa-icon name="arrows-rotate"></wa-icon>
-                        Scan all
-                    </button>
-                </div>
-
-                <div class="card">
-                    ${this.libraries.length === 0
-                        ? html`<div class="empty">
-                              No libraries yet — add one in Settings.
-                          </div>`
-                        : this.libraries.map((lib) =>
-                              this.renderLibraryRow(lib),
-                          )}
-                </div>
-            </section>
-
-            <section>
-                <div class="section-head">
-                    <h2>Maintenance</h2>
-                </div>
-                <div class="card">
-                    <div class="library-row">
-                        <div>
-                            <div class="library-name">Full rescan</div>
-                            <div class="library-meta">
-                                Wipes all library data and cover art, then
-                                rebuilds from your files. Only needed when the
-                                library is corrupt — a normal scan already
-                                picks up changes.
-                            </div>
-                        </div>
-                        <button
-                            class="action danger"
-                            ?disabled=${anyScanning ||
-                            this.starting ||
-                            this.libraries.length === 0}
-                            @click=${this.fullRescan}
-                        >
-                            <wa-icon name="triangle-exclamation"></wa-icon>
-                            Full rescan
-                        </button>
-                    </div>
-                </div>
-            </section>
-
-            ${finished.length > 0
-                ? html`
-                      <section>
-                          <div class="section-head">
-                              <h2>Recently finished</h2>
-                              <button
-                                  class="link"
-                                  @click=${this.clearFinished}
-                              >
-                                  Clear
-                              </button>
-                          </div>
-                          ${this.renderJobList(finished, '')}
-                      </section>
-                  `
-                : nothing}
-
-            <job-details-drawer
-                job-id=${this.drawerJobId}
-                ?open=${this.drawerOpen}
-                @drawer-closed=${this.onDrawerClosed}
-            ></job-details-drawer>
-        `;
-    }
-}
-
-declare global {
-    interface HTMLElementTagNameMap {
-        'jobs-view': JobsView;
-    }
-}

frontend/src/components/now-playing/now-playing.ts

@@ -188,6 +188,27 @@ export class NowPlaying extends LitElement {
         cursor: pointer;
         /* The art shows through; this is a target, not a picture. */
         color: transparent;
+        /* **Above the art, or it is not a target at all** (#150).
+
+           This button is absolutely positioned with z-index auto and
+           the art is a *later* sibling, so the two tie on paint order
+           and the later one wins. With an <img> that costs nothing --
+           an image is not a hit-test obstacle here -- but a track with
+           no artwork renders a placeholder wa-icon, which is, and it
+           takes every click aimed at the button underneath it.
+
+           The failure is therefore per *track*, not per build: on a
+           phone the only way into the full-screen now-playing view
+           stopped working whenever the current song had no cover.
+           Measured with elementFromPoint at the button's centre --
+           wa-icon with a placeholder, button.expand with an image, and
+           button.expand either way once this line exists.
+
+           z-index rather than pointer-events: none on the art, which
+           would take the cover preview's mouseenter with it; and
+           rather than reordering the DOM, which would leave the same
+           tie to be won by the same accident in the other direction. */
+        z-index: 1;
       }
 
       .expand:focus-visible {

frontend/src/components/queue-panel/queue-panel.ts

@@ -277,6 +277,26 @@ export class QueuePanel
         return this.queue.tracks.length;
     }
 
+    /**
+     * Repaint the rows when the selection changes.
+     *
+     * `<lit-virtualizer>` renders through the `virtualize` directive,
+     * which reacts to its *own* properties and not to the host having
+     * re-rendered, so host state like a selection reaches the rows only
+     * if it is pushed. `track-list` has always done this and both
+     * playlist views had to be taught it.
+     *
+     * **There is a second, accidental mechanism here and it must not be
+     * mistaken for this one**: `.keyFunction` below is a per-render
+     * arrow, so it is a changed property on every host update and
+     * repaints the rows by itself. Removing *either* alone changes
+     * nothing observable, which is why #43 could not be settled by
+     * reading the code. With both gone the highlight still arrives —
+     * on whatever unrelated render happens next, measured at 134ms,
+     * 3,866ms and 5,816ms against 5–17ms healthy, which a user cannot
+     * tell from broken. `queue-selection.spec.ts` asserts the
+     * *promptness* rather than the eventual state for that reason.
+     */
     onSelectionChanged(): void {
         this.virtualizer?.requestUpdate();
     }

frontend/src/components/sidebar/app-sidebar.ts

@@ -5,19 +5,9 @@ import { designTokens } from '../../styles/tokens.css';
 
 import type { DragActiveDetail } from '@utils/drag-controller';
 import { ActiveViewController } from '@store/controllers/active-view-controller';
-import {
-    ICON_PLAYLIST,
-    ICON_AUTOTAG,
-    ICON_REQUESTED,
-} from '@utils/icon-language';
-
-type View = 'home' | 'playlists' | 'artists' | 'genres' | 'albums' | 'tracks' | 'explore' | 'downloads' | 'autotag' | 'jobs' | 'settings';
-
-interface NavItem {
-    id: View;
-    label: string;
-    icon: string;
-}
+import { ViewVisibilityController } from '@store/controllers/view-visibility-controller';
+import { VIEW_META } from '../../services/view-meta';
+import type { View } from '../../services/view-meta';
 
 const MIN_WIDTH = 56;
 const MAX_WIDTH = 400;
@@ -210,19 +200,15 @@ export class AppSidebar extends LitElement {
         typeof setTimeout
     > | null = null;
 
-    private navItems: NavItem[] = [
-        { id: 'home', label: 'Home', icon: 'house' },
-        { id: 'playlists', label: 'Playlists', icon: ICON_PLAYLIST },
-        { id: 'artists', label: 'Artists', icon: 'user-group' },
-        { id: 'genres', label: 'Genres', icon: 'masks-theater' },
-        { id: 'albums', label: 'Albums', icon: 'compact-disc' },
-        { id: 'tracks', label: 'Tracks', icon: 'music' },
-        { id: 'explore', label: 'Explore', icon: 'globe' },
-        { id: 'downloads', label: 'Downloads', icon: ICON_REQUESTED },
-        { id: 'autotag', label: 'Autotag', icon: ICON_AUTOTAG },
-        { id: 'jobs', label: 'Jobs', icon: 'list-check' },
-        { id: 'settings', label: 'Settings', icon: 'gear' },
-    ];
+    /**
+     * Which destinations the user has kept (#25). The list below is
+     * still the whole set and its order -- this only filters it, and
+     * only for drawing: a hidden view is still reachable by `navigate`,
+     * which is what detail views and the launch page depend on.
+     */
+    private visibilityCtrl = new ViewVisibilityController(this);
+
+    private navItems = VIEW_META;
 
     override connectedCallback() {
         super.connectedCallback();
@@ -283,7 +269,9 @@ export class AppSidebar extends LitElement {
             ></div>
             <nav aria-label="Main">
             <ul>
-                ${this.navItems.map((item) => {
+                ${this.navItems
+            .filter((item) => this.visibilityCtrl.visible(item.id))
+            .map((item) => {
             const active = this.activeCtrl.isActive(item.id);
             const classes = [
                 active

frontend/src/services/top-bar-fit.ts

@@ -0,0 +1,199 @@
+/**
+ * What the top bar drops when it runs out of room (#143).
+ *
+ * The bar holds five children — the wordmark, back/forward, the library
+ * filter, the search box and the job indicator — and at the bottom of
+ * the Compact band they do not all fit. Measured on `main` at 600×600:
+ * the bar is 611px inside a 600px viewport sitting still, and **862px
+ * while a scan with a long title is running**, because `job-indicator`
+ * is `hidden` when idle and up to 235px wide when it is not. `body` is
+ * `overflow-x: auto`, so what a user sees is a horizontal scrollbar on
+ * a shell that #24 promised would not need one.
+ *
+ * **The fit is measured, never breakpointed**, which is `page-header`'s
+ * rule (#69) and applies here for a reason specific to this bar: three
+ * of its five children are as wide as their *content*. The library
+ * filter is a `<select>` sized by the longest library name, the job
+ * indicator by the running job's title, and the search box by its
+ * view-scoped placeholder — so any width you pick is right for exactly
+ * one library, one job and one view. The same sweep that produced the
+ * numbers above found the bar overflowing at every width from 600 to
+ * 899 *and* at 900, where `nav-history` reappears; a breakpoint fixing
+ * "600 to 610" would have fixed the case that happened to be idle.
+ *
+ * **What yields is chosen by #24's own sentence** — *no action is ever
+ * unreachable at any supported size* — which rules out the two cheapest
+ * candidates the issue lists. Hiding the library filter takes away an
+ * action: `library-filter` is the **only** control in the app that sets
+ * the selected library (nothing else calls `setSelectedLibrary`), so
+ * hiding it is trading this promise for the same promise. Collapsing
+ * the search box to an icon is what #57 wants on a phone, but #57 is
+ * blocked behind #62 and building its modal here would be building it
+ * without the thing that blocks it.
+ *
+ * So the two things that yield are the two that are **not** actions and
+ * whose content survives elsewhere:
+ *
+ * 1. **The wordmark**, which is a brand — the window's own title bar
+ *    says the same thing, and #48 wants it down to "YJ" at every width
+ *    anyway. It yields its *width*, not its existence: the rule in
+ *    `index.css` is visually-hidden rather than `display: none`, so the
+ *    document keeps its top-level heading.
+ * 2. **The job indicator's label**, leaving the ring. This is not a new
+ *    judgement — the component already drops it below 600px for exactly
+ *    this reason, and its `sr-only` live region is what announces the
+ *    state either way, so nothing is lost to anyone. What a measurement
+ *    adds is the band between 600 and 900, where whether the label fits
+ *    depends on what else is in the bar rather than on the width alone.
+ *
+ * Measured against the running app with a long-titled scan staged, that
+ * order fits at every width from 320 to 1440 — and collapses nothing at
+ * 320, 390, 599, 899 and 1100, which is the other half of the claim.
+ *
+ * Three things about the mechanism are load-bearing.
+ *
+ * **Every pass starts from all-visible**, so the collapsed set is a
+ * pure function of the current width rather than of how the window got
+ * there. `page-header` states the same rule and the same reasons: a
+ * pass that only ever added would never give the wordmark back, and one
+ * that adjusted by a step would need a hysteresis band to stop it
+ * oscillating on the pixel where it exactly fits.
+ *
+ * **"Fits" is the children against the content box, not `scrollWidth`
+ * against `clientWidth`** — and that distinction is not pedantry, it
+ * is a measured false pass. `scrollWidth` counts a box's *left*
+ * padding and not its right, so with this bar's 2em gutters it
+ * under-reports by 32px: at 700px with a scan running it read
+ * `700/700`, a perfect fit, while `job-indicator` ended 32px past
+ * where the content may go and sat in the gutter. Same family as #69's
+ * title trap, one property over — the measurement that is easiest to
+ * reach for is the one that cannot see the failure. So the predicate
+ * here is the same one `top-bar-fit.spec.ts` asserts: no in-flow child
+ * outside the content box.
+ *
+ * That is only truthful in turn because **nothing here absorbs pressure
+ * by truncating**. The collapsible children are `flex-shrink: 0` in
+ * `index.css`, so a deficit shows up as a child out of bounds instead
+ * of quietly eating the indicator's label, which is `text-overflow:
+ * ellipsis` and would have. The search box is the one child that may
+ * shrink, between its 320px basis and the 200px floor its own
+ * stylesheet sets, and a narrower input hides nothing it was showing.
+ *
+ * **The bar does not resize when a job starts**, which is the case the
+ * whole thing is for. A ResizeObserver on the header alone never fires:
+ * the indicator goes 0 → 235 inside a bar whose width has not changed.
+ * Every element child is observed too.
+ */
+
+/** One thing the bar can give up, cheapest first. */
+interface FitStep {
+    /** For tests and for reading the DOM back. */
+    readonly id: string;
+    /** Applied to the bar; `on` collapses. */
+    readonly collapse: (bar: HTMLElement, on: boolean) => void;
+}
+
+/**
+ * The order things are given up in. Lowest priority first — see the
+ * argument above for why these two and not the library filter.
+ */
+export const FIT_STEPS: readonly FitStep[] = [
+    {
+        id: 'wordmark',
+        collapse: (bar, on) =>
+            bar.querySelector('hgroup')?.classList.toggle('yj-collapsed', on),
+    },
+    {
+        id: 'job-label',
+        collapse: (bar, on) =>
+            bar.querySelector('job-indicator')?.toggleAttribute('compact', on),
+    },
+];
+
+/**
+ * Decide what the bar shows at its current width.
+ *
+ * Exported for the component tier, which can hand it a bar of known
+ * widths; the app installs the observer below and never calls this.
+ *
+ * @returns the ids collapsed, in the order they were given up.
+ */
+export function measureTopBarFit(bar: HTMLElement): string[] {
+    const fits = () => {
+        const style = getComputedStyle(bar);
+        const box = bar.getBoundingClientRect();
+        const left = box.left + parseFloat(style.paddingLeft);
+        const right = box.right - parseFloat(style.paddingRight);
+
+        for (const child of bar.children) {
+            const cs = getComputedStyle(child);
+
+            // Out of flow is out of the question: a collapsed wordmark
+            // is absolutely positioned and 1px wide precisely so that
+            // it costs the row nothing.
+            if (cs.display === 'none' || cs.position === 'absolute') continue;
+
+            const r = child.getBoundingClientRect();
+
+            // Sub-pixel slack: a flex row's widths are fractional and a
+            // rounding difference is not an overflow anyone can see.
+            if (r.width > 0 && (r.right > right + 0.5 || r.left < left - 0.5)) {
+                return false;
+            }
+        }
+
+        return true;
+    };
+
+    for (const step of FIT_STEPS) step.collapse(bar, false);
+
+    const collapsed: string[] = [];
+
+    if (!fits()) {
+        for (const step of FIT_STEPS) {
+            step.collapse(bar, true);
+            collapsed.push(step.id);
+
+            if (fits()) break;
+        }
+    }
+
+    return collapsed;
+}
+
+/**
+ * Watch the bar and its children, and keep it fitting.
+ *
+ * Returns the uninstaller, which the tests use; the app installs once
+ * for the life of the session.
+ */
+export function installTopBarFit(bar: HTMLElement): () => void {
+    let measuring = false;
+
+    const measure = () => {
+        // A pass resizes the children it collapses, which the observer
+        // would report back to us. It settles either way — the pass is
+        // idempotent at a given width — but re-entering it is work for
+        // no news, and it is what "ResizeObserver loop completed with
+        // undelivered notifications" is.
+        if (measuring) return;
+
+        measuring = true;
+
+        try {
+            measureTopBarFit(bar);
+        } finally {
+            measuring = false;
+        }
+    };
+
+    const observer = new ResizeObserver(measure);
+
+    observer.observe(bar);
+
+    for (const child of bar.children) observer.observe(child);
+
+    measure();
+
+    return () => observer.disconnect();
+}

frontend/src/services/view-meta.ts

@@ -0,0 +1,64 @@
+import {
+    ICON_PLAYLIST,
+    ICON_AUTOTAG,
+    ICON_REQUESTED,
+} from '@utils/icon-language';
+
+/** A primary destination. Mirrors `backend/config.View`. */
+export type View =
+    | 'home'
+    | 'playlists'
+    | 'artists'
+    | 'genres'
+    | 'albums'
+    | 'tracks'
+    | 'explore'
+    | 'downloads'
+    | 'autotag'
+    | 'settings';
+
+export interface ViewMeta {
+    id: View;
+    label: string;
+    icon: string;
+    /**
+     * Views that are never offered as a toggle. Settings alone, because
+     * a user who hides it cannot get back to unhide it.
+     *
+     * This is the *affordance*; the rule is `backend/config.ViewSpec`'s
+     * `Hideable`, which refuses at the setter and drops the key on load.
+     * `config.toml` is hand-editable, so the checkbox being absent is
+     * not what makes this safe — it is only what stops the question
+     * being asked.
+     */
+    alwaysShown?: boolean;
+}
+
+/**
+ * The app's primary destinations, in the order the navigation draws
+ * them and Settings lists them.
+ *
+ * It is here rather than inside `app-sidebar` because #25 gave it a
+ * second reader: Settings renders a toggle per view and needs the same
+ * labels in the same order. Same shape as `services/shortcut-meta.ts`,
+ * which moved out of `config-page` for the same reason -- a private
+ * static that two surfaces need is a private static that is about to be
+ * copied.
+ *
+ * The labels and icons deliberately do not exist in Go. Which views
+ * exist and what an unconfigured install shows is `backend/config.Views`
+ * and is asked for over the binding; how they are *drawn* is the
+ * frontend's, and lives beside the rest of the icon vocabulary.
+ */
+export const VIEW_META: ViewMeta[] = [
+    { id: 'home', label: 'Home', icon: 'house' },
+    { id: 'playlists', label: 'Playlists', icon: ICON_PLAYLIST },
+    { id: 'artists', label: 'Artists', icon: 'user-group' },
+    { id: 'genres', label: 'Genres', icon: 'masks-theater' },
+    { id: 'albums', label: 'Albums', icon: 'compact-disc' },
+    { id: 'tracks', label: 'Tracks', icon: 'music' },
+    { id: 'explore', label: 'Explore', icon: 'globe' },
+    { id: 'downloads', label: 'Downloads', icon: ICON_REQUESTED },
+    { id: 'autotag', label: 'Autotag', icon: ICON_AUTOTAG },
+    { id: 'settings', label: 'Settings', icon: 'gear', alwaysShown: true },
+];

frontend/src/store/controllers/view-visibility-controller.ts

@@ -0,0 +1,54 @@
+import type {
+    ReactiveController,
+    ReactiveControllerHost,
+} from 'lit';
+import { viewVisibilityStore } from '../view-visibility-store';
+
+/**
+ * ViewVisibilityController connects a Lit component to the
+ * ViewVisibilityStore.
+ *
+ * It reads through to the store rather than copying the map into a
+ * `@state()` field, for the reason `ActiveViewController` does: there
+ * are two live `<app-sidebar>` instances the moment `bottom-nav`'s
+ * "More" drawer opens, and two components holding their own idea of
+ * which destinations exist is how they come to disagree.
+ */
+export class ViewVisibilityController implements ReactiveController {
+    private host: ReactiveControllerHost;
+    private unsubscribe?: () => void;
+
+    constructor(host: ReactiveControllerHost) {
+        this.host = host;
+        host.addController(this);
+    }
+
+    hostConnected(): void {
+        this.unsubscribe = viewVisibilityStore.subscribe(() => {
+            this.host.requestUpdate();
+        });
+
+        void viewVisibilityStore.init();
+    }
+
+    hostDisconnected(): void {
+        this.unsubscribe?.();
+    }
+
+    /** Whether the navigation should offer this destination. */
+    visible(view: string): boolean {
+        return viewVisibilityStore.visible(view);
+    }
+
+    /**
+     * What the config says, ignoring the download-client gate — the
+     * state Settings' own checkbox shows.
+     */
+    enabled(view: string): boolean {
+        return viewVisibilityStore.enabled(view);
+    }
+
+    setVisible(view: string, visible: boolean): Promise<void> {
+        return viewVisibilityStore.setVisible(view, visible);
+    }
+}

frontend/src/store/download-store.ts

@@ -189,6 +189,8 @@ class DownloadStore {
 
     private initialized = false;
 
+    private providersLoaded = false;
+
     constructor() {
         EventsOn(Events.DownloadProvidersChanged, () => {
             void this.refreshProviders();
@@ -285,6 +287,25 @@ class DownloadStore {
         }
     }
 
+    /**
+     * Loads the providers, and only those, once.
+     *
+     * `init()` additionally fetches the descriptors, the downloads and
+     * the request list, which is right for a page about downloading and
+     * wrong for the sidebar: it only needs `available`, to decide
+     * whether the Downloads destination exists at all (#25), and that
+     * is one query. `DownloadProvidersChanged` keeps it current
+     * afterwards, so configuring a client makes the tab appear without
+     * a restart.
+     */
+    async ensureProviders(): Promise<void> {
+        if (this.providersLoaded) return;
+
+        this.providersLoaded = true;
+
+        await this.refreshProviders();
+    }
+
     async refreshProviders(): Promise<void> {
         try {
             this.providersValue = (await ListProviders()) ?? [];

frontend/src/store/job-store.ts

@@ -30,6 +30,7 @@ export type JobState =
 export type JobKind =
     | 'library-scan'
     | 'index-build'
+    | 'download'
     | 'autotag-apply'
     | 'catalog-enrich';
 

frontend/src/store/view-visibility-store.ts

@@ -0,0 +1,119 @@
+import { EventsOn } from '@runtime/runtime';
+import { GetViewVisibility, SetViewVisible } from '@go/config/config.js';
+import { dictByName } from '@utils/binding';
+import { downloadStore } from './download-store';
+import { Events } from '../events';
+
+type Subscriber = () => void;
+
+/**
+ * Which primary destinations the navigation offers.
+ *
+ * Eleven sidebar entries is more than most libraries need, so #25 makes
+ * them individually toggleable. Three rules about this are load-bearing.
+ *
+ * **Hidden is not unreachable.** This decides what the *nav* draws and
+ * nothing else: `navigate` still resolves a hidden view, which is not a
+ * nicety — detail views navigate into these, and the shell's launch
+ * page is one of them. Nothing here needs a special case for the
+ * highlight either, because #72 moved that onto `active-view-store`:
+ * `app-sidebar` asks `isActive(id)` per *rendered* item, so a hidden
+ * view lights nothing exactly as a detail view does.
+ *
+ * **The defaults live in Go**, in `backend/config.Views`, and this asks
+ * for the *resolved* answer rather than the stored map. A config that
+ * says nothing about a view means "that view's own default", so a copy
+ * of the defaults here would be a second thing to keep in step — and
+ * the one that shipped in the artifact, not the one being edited.
+ *
+ * **Downloads is a second question**, answered by the download client
+ * rather than by the config: a destination for a feature that cannot
+ * work is worse than an absent one. It is gated at `visible()` and not
+ * in the config, so switching it on in Settings still means what it
+ * says once a client exists. `available` is false until the providers
+ * have loaded, which makes the tab *appear* on a fresh launch rather
+ * than appearing and then vanishing — the less jarring half of a race
+ * that resolves in one query.
+ */
+class ViewVisibilityStore {
+    /** The backend's resolved answer, empty until the first load. */
+    private configured: Record<string, boolean> = {};
+
+    private loaded = false;
+
+    private subscribers = new Set<Subscriber>();
+
+    constructor() {
+        EventsOn(Events.GeneralConfigChanged, () => {
+            void this.refresh();
+        });
+
+        // A client configured later has to add the destination without a
+        // restart -- #37's rule, one surface over.
+        downloadStore.subscribe(() => this.notify());
+    }
+
+    /** Loads the visibility map once. Safe to call from every mount. */
+    async init(): Promise<void> {
+        if (this.loaded) return;
+
+        this.loaded = true;
+
+        await Promise.all([
+            this.refresh(),
+            downloadStore.ensureProviders(),
+        ]);
+    }
+
+    /**
+     * Whether the navigation should offer this destination.
+     *
+     * An unknown id is visible: the caller is drawing it from its own
+     * list, and a view this store has not heard of (or has not loaded
+     * yet) is better shown than silently dropped.
+     */
+    visible(view: string): boolean {
+        if (view === 'downloads' && !downloadStore.available) return false;
+
+        return this.configured[view] ?? true;
+    }
+
+    /**
+     * What the *config* says, ignoring the download-client gate — which
+     * is what Settings' own checkbox has to show, or a user with no
+     * client would see Downloads switched off and be unable to switch
+     * it on.
+     */
+    enabled(view: string): boolean {
+        return this.configured[view] ?? true;
+    }
+
+    async setVisible(view: string, visible: boolean): Promise<void> {
+        await SetViewVisible(view, visible);
+
+        // The backend emits GeneralConfigChanged, but the caller is
+        // owed the new state by the time this resolves.
+        await this.refresh();
+    }
+
+    subscribe(fn: Subscriber): () => void {
+        this.subscribers.add(fn);
+
+        return () => this.subscribers.delete(fn);
+    }
+
+    private async refresh(): Promise<void> {
+        try {
+            this.configured = await dictByName(GetViewVisibility());
+            this.notify();
+        } catch (err) {
+            console.error('Failed to load view visibility:', err);
+        }
+    }
+
+    private notify(): void {
+        this.subscribers.forEach((fn) => fn());
+    }
+}
+
+export const viewVisibilityStore = new ViewVisibilityStore();

frontend/src/store/volume-style-store.ts

@@ -0,0 +1,85 @@
+import { EventsOn } from '@runtime/runtime';
+import { GetPopupVolume } from '@go/config/config.js';
+import { Events } from '../events';
+
+type Subscriber = () => void;
+
+/**
+ * Whether the volume control is a click-to-open popup (#42).
+ *
+ * The popup was the only option, and "click open, drag, click closed"
+ * is three gestures for a control a bottom bar has room to just show.
+ * So an inline slider is the default and the popup is a setting.
+ *
+ * **The stored flag names the popup, not the slider**, which is the
+ * polarity rule `backend/config` states for every option it has: the
+ * zero value has to be the intended answer. An `InlineVolume bool`
+ * would default to false, hand the popup to every existing install, and
+ * need a migration to say what the default already says.
+ *
+ * It is a store rather than a field on the component because two
+ * components render `<volume-control>` — the bottom bar and the phone's
+ * full-screen now-playing view — and a setting that only reached
+ * whichever one happened to mount after it changed is the fault
+ * `active-view-store` exists to prevent, one surface over.
+ *
+ * The initial value is the *default* rather than a pending answer, so
+ * the first paint is the inline slider and not an empty gap that
+ * becomes one. An install that has chosen the popup sees it swap once
+ * on load, which is the cheaper of the two wrong first frames: the
+ * inline slider occupies the space the popup's button would have.
+ */
+class VolumeStyleStore {
+    private value = false;
+
+    private loaded = false;
+
+    private subscribers = new Set<Subscriber>();
+
+    constructor() {
+        EventsOn(Events.GeneralConfigChanged, () => {
+            void this.refresh();
+        });
+    }
+
+    /** Whether to draw the popup. Safe to read before `init()`. */
+    get popup(): boolean {
+        return this.value;
+    }
+
+    /** Reads the setting once. Safe to call from every mount. */
+    async init(): Promise<void> {
+        if (this.loaded) return;
+
+        this.loaded = true;
+
+        await this.refresh();
+    }
+
+    subscribe(fn: Subscriber): () => void {
+        this.subscribers.add(fn);
+
+        return () => this.subscribers.delete(fn);
+    }
+
+    private async refresh(): Promise<void> {
+        try {
+            const popup = await GetPopupVolume();
+
+            if (popup === this.value) return;
+
+            this.value = popup;
+            this.notify();
+        } catch (err) {
+            // Nothing to tell the user: the control renders in its
+            // default presentation, which is a working volume control.
+            console.error('failed to read the volume control setting', err);
+        }
+    }
+
+    private notify(): void {
+        for (const fn of this.subscribers) fn();
+    }
+}
+
+export const volumeStyleStore = new VolumeStyleStore();

frontend/test/components/chrome.test.ts

@@ -26,7 +26,26 @@ import {
   ICON_REQUESTED,
 } from '@utils/icon-language';
 
+/** A configured, enabled download client. */
+const PROVIDER = {
+  id: 1,
+  kind: 'slskd',
+  name: 'Sound',
+  enabled: true,
+  priority: 50,
+};
+
 describe('<app-sidebar>', () => {
+  // Downloads is offered only where there is a client to download with
+  // (#25), so "all eleven destinations" is a statement about a
+  // configured install. `view-visibility.test.ts` owns the rule itself;
+  // this states the world these cases are describing.
+  beforeEach(async () => {
+    stub('download.Service.ListProviders', [PROVIDER]);
+    emit(Events.DownloadProvidersChanged);
+    await flush();
+  });
+
   it('renders a testid per destination, which is how e2e navigates', async () => {
     const el = await fixture('app-sidebar');
 
@@ -44,7 +63,6 @@ describe('<app-sidebar>', () => {
       'nav-explore',
       'nav-downloads',
       'nav-autotag',
-      'nav-jobs',
       'nav-settings',
     ]);
   });

frontend/test/components/job-panel.test.ts

@@ -0,0 +1,160 @@
+/**
+ * Background work, shown where the work is started (#27).
+ *
+ * The Jobs tab is gone; each kind's rows now live beside the thing that
+ * starts it — scans in Settings → Libraries, index work in Search
+ * Index, downloads under the download clients, the autotag apply in the
+ * Autotag view. What those four surfaces never had, and what this
+ * carries to them, is the *generic* affordances: pause, cancel,
+ * "Details", and a finished job you can dismiss.
+ *
+ * The assertions are about which rows a panel owns and what its buttons
+ * do, not about the store — `job-store` already has the snapshot
+ * covered, and a panel that renders the right rows for the wrong reason
+ * would pass either way.
+ */
+import { describe, expect, it, beforeEach } from 'vitest';
+
+import '@components/jobs/job-panel';
+import { emit, flush, lastArgs, calls, resetHarness, stub } from '@test/support/harness';
+import { Events } from '../../src/events';
+import { fixture, shadow, shadowAll } from '@test/support/render';
+import type { LitElement } from 'lit';
+
+/** A job snapshot entry, with the fields `job-row` actually reads. */
+const job = (over: Record<string, unknown> = {}) => ({
+  id: 'scan:1',
+  kind: 'library-scan',
+  title: 'Scanning Music',
+  state: 'running',
+  current: 3,
+  total: 10,
+  caps: { pausable: true, cancellable: true },
+  stages: null,
+  stats: null,
+  startedAt: Date.now(),
+  updatedAt: Date.now(),
+  logCount: 0,
+  warnCount: 0,
+  errorCount: 0,
+  ...over,
+});
+
+/** Push a full snapshot, which is what the backend emits. */
+async function snapshot(jobs: unknown[]): Promise<void> {
+  emit(Events.JobsChanged, jobs);
+  await flush();
+}
+
+const rows = (el: HTMLElement) => shadowAll(el, 'job-row');
+
+const titles = (el: HTMLElement) =>
+  rows(el).map((row) => (row as HTMLElement & { job: { title: string } }).job.title);
+
+describe('<job-panel>', () => {
+  beforeEach(async () => {
+    resetHarness();
+    stub('jobs.Service.GetJobs', []);
+    await snapshot([]);
+  });
+
+  it('renders only the kinds it was asked for', async () => {
+    const el = await fixture<LitElement>('job-panel', {
+      kinds: 'index-build,catalog-enrich',
+    });
+
+    await snapshot([
+      job({ id: 'scan:1', kind: 'library-scan', title: 'Scanning Music' }),
+      job({ id: 'idx', kind: 'index-build', title: 'Building the index' }),
+      job({ id: 'enrich', kind: 'catalog-enrich', title: 'Filling in artists' }),
+    ]);
+    await el.updateComplete;
+
+    // The title is inside `job-row`'s own shadow root, so this asks
+    // the rows what they are drawing rather than reading the panel's
+    // text -- which would pass whether or not a row rendered.
+    expect(titles(el)).toEqual(['Building the index', 'Filling in artists']);
+  });
+
+  /**
+   * An idle panel in four places is four pieces of furniture describing
+   * an absence — and `hidden` rather than an empty render, because the
+   * host's own margin would otherwise still be spent.
+   */
+  it('takes up no room when it has nothing to say', async () => {
+    const el = await fixture<LitElement>('job-panel', { kinds: 'download' });
+
+    await snapshot([job({ id: 'scan:1', kind: 'library-scan' })]);
+    await el.updateComplete;
+
+    expect(el.hidden).toBe(true);
+    expect(rows(el)).toHaveLength(0);
+
+    await snapshot([
+      job({ id: 'dl:1', kind: 'download', title: 'Downloading Glass Harbour' }),
+    ]);
+    await el.updateComplete;
+
+    expect(el.hidden).toBe(false);
+    expect(rows(el)).toHaveLength(1);
+  });
+
+  /**
+   * The controls go through `applyJobControl`, which is what carries
+   * the index build's "you will discard hours of downloading"
+   * confirmation across this move. A host drawing its own buttons would
+   * have dropped it silently.
+   */
+  it('pauses through the shared handler', async () => {
+    const el = await fixture<LitElement>('job-panel', { kinds: 'library-scan' });
+
+    await snapshot([job()]);
+    await el.updateComplete;
+
+    const row = rows(el)[0]!;
+
+    shadow<HTMLButtonElement>(row, 'button[aria-label^="Pause"]')?.click();
+    await flush();
+
+    expect(lastArgs('jobs.Service.PauseJob')).toEqual(['scan:1']);
+  });
+
+  /**
+   * Cancelling an index build asks first; cancelling a scan does not,
+   * because a scan is cheap to re-run. Both answers live in
+   * `applyJobControl` and both had to survive the move.
+   */
+  it('does not ask before cancelling a scan', async () => {
+    const el = await fixture<LitElement>('job-panel', { kinds: 'library-scan' });
+
+    await snapshot([job()]);
+    await el.updateComplete;
+
+    const row = rows(el)[0]!;
+
+    shadow<HTMLButtonElement>(row, 'button[aria-label^="Stop"]')?.click();
+    await flush();
+
+    expect(lastArgs('jobs.Service.CancelJob')).toEqual(['scan:1']);
+  });
+
+  /**
+   * A finished job is dismissed one at a time. There is deliberately no
+   * "Clear finished" here: `ClearFinishedJobs` is global, so a Clear in
+   * the Libraries panel would discard the index build's history too.
+   */
+  it('keeps finished jobs, dismissible one by one', async () => {
+    const el = await fixture<LitElement>('job-panel', { kinds: 'library-scan' });
+
+    await snapshot([job({ state: 'complete' })]);
+    await el.updateComplete;
+
+    const row = rows(el)[0]!;
+
+    shadow<HTMLButtonElement>(row, 'button[aria-label^="Dismiss"]')?.click();
+    await flush();
+
+    expect(lastArgs('jobs.Service.DismissJob')).toEqual(['scan:1']);
+    expect(calls('jobs.Service.ClearFinishedJobs')).toHaveLength(0);
+  });
+});

frontend/test/components/keyboard-reach.test.ts

@@ -11,7 +11,8 @@ import { describe, expect, it, beforeEach } from 'vitest';
 import '@components/sidebar/app-sidebar';
 import '@components/queue-panel/queue-panel';
 import '@components/track-list/track-list';
-import { stub } from '@test/support/harness';
+import { stub, emit, flush } from '@test/support/harness';
+import { Events } from '../../src/events';
 import { fixture, shadow, shadowAll, update } from '@test/support/render';
 
 /** Two fixture tracks, enough to move a focus ring between. */
@@ -33,12 +34,22 @@ const TRACKS = [
 ] as never[];
 
 describe('<app-sidebar> is reachable', () => {
+  // Eleven destinations assumes a configured download client, since
+  // Downloads is not offered without one (#25).
+  beforeEach(async () => {
+    stub('download.Service.ListProviders', [
+      { id: 1, kind: 'slskd', name: 'Sound', enabled: true, priority: 50 },
+    ]);
+    emit(Events.DownloadProvidersChanged);
+    await flush();
+  });
+
   it('renders every destination as a button, not a bare list item', async () => {
     const el = await fixture('app-sidebar');
 
     const items = shadowAll(el, 'li button');
 
-    expect(items).toHaveLength(11);
+    expect(items).toHaveLength(10);
     expect(items.every((item) => item.tagName === 'BUTTON')).toBe(true);
   });
 

frontend/test/components/smoke.test.ts

@@ -40,7 +40,7 @@ import '@components/jobs/job-details-drawer';
 import '@components/jobs/job-indicator';
 import '@components/jobs/job-log-view';
 import '@components/jobs/job-row';
-import '@components/jobs/jobs-view';
+import '@components/jobs/job-panel';
 import '@components/library-filter/library-filter';
 import '@components/library-status-indicator/library-status-indicator';
 import '@components/now-playing/now-playing';
@@ -87,8 +87,8 @@ const TAGS = [
   'job-details-drawer',
   'job-indicator',
   'job-log-view',
+  'job-panel',
   'job-row',
-  'jobs-view',
   'library-filter',
   'library-status-indicator',
   'now-playing',

frontend/test/components/transport.test.ts

@@ -11,7 +11,7 @@ import '@components/audio-player/controls/player-controls';
 import '@components/audio-player/seekbar/seek-bar';
 import '@components/audio-player/volume-control/volume-control';
 import { Events } from '../../src/events';
-import { emit, calls, lastArgs, flush } from '@test/support/harness';
+import { emit, calls, lastArgs, flush, stub } from '@test/support/harness';
 import {
   fixture,
   shadow,
@@ -434,13 +434,40 @@ describe('<seek-bar>', () => {
  * be driven by its own event — watching the volume number, as it used
  * to, meant pressing M visibly did nothing.
  */
+/**
+ * The volume control has two presentations (#42), and the icon button
+ * means a different thing in each — so both are exercised rather than
+ * whichever one happens to be the default.
+ *
+ * Inline is the default: the slider is simply there, which leaves the
+ * icon with nothing to disclose, so it is the mute toggle and is named
+ * after that action. In the popup it is a disclosure, so it is named
+ * after the *state* it is showing.
+ */
 describe('volume control: mute', () => {
-  beforeEach(() => {
+  /**
+   * Put the presentation back to the default between tests.
+   *
+   * `volumeStyleStore` is a singleton whose `init()` reads the setting
+   * once, so stubbing the binding inside a test is too late — a
+   * previous test has already loaded it. `GeneralConfigChanged` is the
+   * store's own refresh trigger and the same one the Settings page
+   * fires, so driving it that way exercises the real path instead of
+   * reaching for a test-only reset.
+   */
+  const setPresentation = async (popup: boolean) => {
+    stub('config.Config.GetPopupVolume', popup);
+    emit(Events.GeneralConfigChanged, {});
+    await flush();
+  };
+
+  beforeEach(async () => {
+    await setPresentation(false);
     emit(Events.VolumeChanged, 40);
     emit(Events.MuteChanged, false);
   });
 
-  it('shows a muted glyph and label once the backend reports mute', async () => {
+  it('shows a muted glyph once the backend reports mute', async () => {
     const el = await fixture('volume-control');
 
     expect(shadow(el, 'button')?.getAttribute('data-muted')).toBe('false');
@@ -453,14 +480,53 @@ describe('volume control: mute', () => {
     expect(shadow(el, 'button wa-icon')?.getAttribute('name')).toBe(
       'volume-xmark',
     );
+  });
+
+  it('names the inline icon after the action it performs', async () => {
+    const el = await fixture('volume-control');
+
+    expect(shadow(el, 'button')?.getAttribute('aria-label')).toBe('Mute');
+
+    emit(Events.MuteChanged, true);
+    await flush();
+    await el.updateComplete;
+
+    expect(shadow(el, 'button')?.getAttribute('aria-label')).toBe('Unmute');
+  });
+
+  it('names the popup icon after the state it discloses', async () => {
+    await setPresentation(true);
+
+    const el = await fixture('volume-control');
+
+    await el.updateComplete;
+
+    expect(shadow(el, 'button')?.getAttribute('aria-label')).toBe(
+      'Volume 40%',
+    );
+
+    emit(Events.MuteChanged, true);
+    await flush();
+    await el.updateComplete;
+
     expect(shadow(el, 'button')?.getAttribute('aria-label')).toBe('Muted');
   });
 
+  it('shows the slider without a click when it is inline', async () => {
+    const el = await fixture('volume-control');
+
+    // The whole point of the issue: no disclosure to operate first.
+    expect(shadow<HTMLInputElement>(el, 'wa-slider')?.value).toBe(40);
+  });
+
   it('keeps showing the volume level while muted, because it is unchanged', async () => {
+    await setPresentation(true);
     emit(Events.MuteChanged, true);
     await flush();
 
     const el = await fixture('volume-control');
+
+    await el.updateComplete;
     await click(el, 'button');
 
     expect(shadow<HTMLInputElement>(el, 'wa-slider')?.value).toBe(40);
@@ -468,11 +534,24 @@ describe('volume control: mute', () => {
 
   it('toggles mute through the backend rather than locally', async () => {
     const el = await fixture('volume-control');
+
+    await click(el, 'button');
+
+    expect(calls('player.Player.MuteToggle').length).toBe(1);
+    // Nothing optimistic: the icon follows the backend's event.
+    expect(shadow(el, 'button')?.getAttribute('data-muted')).toBe('false');
+  });
+
+  it('toggles mute from inside the popup, where the icon is a disclosure', async () => {
+    await setPresentation(true);
+
+    const el = await fixture('volume-control');
+
+    await el.updateComplete;
     await click(el, 'button');
     await click(el, '.mute-toggle');
 
     expect(calls('player.Player.MuteToggle').length).toBe(1);
-    // Nothing optimistic: the icon follows the backend's event.
     expect(shadow(el, 'button')?.getAttribute('data-muted')).toBe('false');
   });
 });

frontend/test/components/view-lifecycle.test.ts

@@ -27,7 +27,6 @@ import '@components/explore-view/explore-view';
 import '@components/home-view/home-view';
 import '@components/downloads-view/downloads-view';
 
-import '@components/jobs/jobs-view';
 import '@components/playlist-view/playlist-view';
 import { fixture } from '@test/support/render';
 import { stub, flush } from '@test/support/harness';
@@ -223,7 +222,6 @@ const CACHED_VIEWS = [
   'artists-view',
   'genres-view',
   'downloads-view',
-  'jobs-view',
   'playlist-view',
   'explore-view',
   'home-view',

frontend/test/components/view-visibility.test.ts

@@ -0,0 +1,189 @@
+/**
+ * Which destinations the navigation offers (#25).
+ *
+ * Eleven sidebar entries is more than most libraries need, so they are
+ * individually toggleable. The assertions here are about the **nav**
+ * and not about the setting being saved: "the config was written" is
+ * the plumbing, and a spec that measures the plumbing is how #69 and
+ * #72 both shipped green on a broken build.
+ *
+ * Two singletons make ordering matter, and both are driven the way the
+ * app drives them rather than reset: `GeneralConfigChanged` is what the
+ * backend emits when a toggle is saved, and `DownloadProvidersChanged`
+ * is what it emits when a client is configured. So each case states the
+ * world it wants and is independent of which one ran first.
+ */
+import { describe, expect, it, beforeEach } from 'vitest';
+
+import '@components/sidebar/app-sidebar';
+import '@components/bottom-nav/bottom-nav';
+import { activeViewStore } from '@store/active-view-store';
+import { stub, emit, flush, resetHarness } from '@test/support/harness';
+import { Events } from '../../src/events';
+import { fixture, shadowAll } from '@test/support/render';
+import type { LitElement } from 'lit';
+
+const PROVIDER = {
+  id: 1,
+  kind: 'slskd',
+  name: 'Sound',
+  enabled: true,
+  priority: 50,
+};
+
+/** Every view id the sidebar is currently drawing, in order. */
+const navIDs = (el: HTMLElement) =>
+  shadowAll<HTMLButtonElement>(el, 'nav button')
+    .map((b) => b.dataset.testid?.replace(/^nav-/, ''))
+    .filter((id): id is string => id !== undefined);
+
+const tabIDs = (el: HTMLElement) =>
+  shadowAll<HTMLButtonElement>(el, 'nav button')
+    .map((b) => b.dataset.testid?.replace(/^tab-/, ''))
+    .filter((id): id is string => id !== undefined);
+
+/**
+ * State the backend's resolved answer and push the event that says it
+ * changed. The map is *resolved* — every known view, defaults already
+ * applied — because that is what the binding returns and the whole
+ * reason the frontend holds no copy of the defaults.
+ */
+async function setViews(views: Record<string, boolean>): Promise<void> {
+  stub('config.Config.GetViewVisibility', views);
+  emit(Events.GeneralConfigChanged, {});
+  await flush();
+  await flush();
+}
+
+async function setClientConfigured(configured: boolean): Promise<void> {
+  stub('download.Service.ListProviders', configured ? [PROVIDER] : []);
+  emit(Events.DownloadProvidersChanged);
+  await flush();
+  await flush();
+}
+
+const ALL_VISIBLE = {
+  home: true,
+  playlists: true,
+  artists: true,
+  genres: true,
+  albums: true,
+  tracks: true,
+  explore: true,
+  downloads: true,
+  autotag: true,
+  settings: true,
+};
+
+describe('view visibility', () => {
+  beforeEach(async () => {
+    resetHarness();
+    await setViews(ALL_VISIBLE);
+    await setClientConfigured(true);
+  });
+
+  it('draws every destination the config keeps', async () => {
+    const el = await fixture<LitElement>('app-sidebar');
+
+    expect(navIDs(el)).toEqual([
+      'home',
+      'playlists',
+      'artists',
+      'genres',
+      'albums',
+      'tracks',
+      'explore',
+      'downloads',
+      'autotag',
+      'settings',
+    ]);
+  });
+
+  it('drops the ones the user switched off', async () => {
+    const el = await fixture<LitElement>('app-sidebar');
+
+    await setViews({ ...ALL_VISIBLE, autotag: false, explore: false });
+    await el.updateComplete;
+
+    expect(navIDs(el)).not.toContain('autotag');
+    expect(navIDs(el)).not.toContain('explore');
+    expect(navIDs(el)).toContain('settings');
+  });
+
+  /**
+   * Hiding is about the nav item, not about the view. Detail views
+   * navigate into these and the launch page is one of them, so the
+   * shell's own statement of where the user is has to survive a
+   * destination that draws no item — and it does so with no special
+   * case here, because #72 moved the highlight onto `active-view-store`
+   * and this only filters what is rendered.
+   */
+  it('lights nothing when the active view is a hidden one', async () => {
+    const el = await fixture<LitElement>('app-sidebar');
+
+    await setViews({ ...ALL_VISIBLE, autotag: false });
+    activeViewStore.setView('autotag', true);
+    await el.updateComplete;
+
+    const lit = shadowAll<HTMLButtonElement>(el, 'nav button')
+      .filter((b) => b.getAttribute('aria-current') === 'page');
+
+    expect(lit).toHaveLength(0);
+    expect(navIDs(el)).not.toContain('autotag');
+
+    activeViewStore.setView('albums', true);
+  });
+
+  /**
+   * A destination for a feature that cannot work is worse than an
+   * absent one, so Downloads asks the download client rather than the
+   * config — and it appears when one is configured, without a restart
+   * (#37's rule, one surface over).
+   */
+  it('hides Downloads until a client is configured', async () => {
+    const el = await fixture<LitElement>('app-sidebar');
+
+    await setClientConfigured(false);
+    await el.updateComplete;
+
+    expect(navIDs(el)).not.toContain('downloads');
+
+    await setClientConfigured(true);
+    await el.updateComplete;
+
+    expect(navIDs(el)).toContain('downloads');
+  });
+
+  /**
+   * The tab bar honours the toggles too, and the reason is local: its
+   * "More" drawer opens the same `<app-sidebar>`, which filters. An
+   * unfiltered bar would contradict its own drawer one tap away.
+   */
+  it('drops a hidden destination from the phone tab bar', async () => {
+    const el = await fixture<LitElement>('bottom-nav');
+
+    expect(tabIDs(el)).toEqual(['home', 'albums', 'tracks', 'playlists', 'more']);
+
+    await setViews({ ...ALL_VISIBLE, albums: false });
+    await el.updateComplete;
+
+    expect(tabIDs(el)).toEqual(['home', 'tracks', 'playlists', 'more']);
+  });
+
+  /** "More" is not a destination and is never filtered away: it is how
+   *  everything else is still reachable. */
+  it('keeps More when every tab is hidden', async () => {
+    const el = await fixture<LitElement>('bottom-nav');
+
+    await setViews({
+      ...ALL_VISIBLE,
+      home: false,
+      albums: false,
+      tracks: false,
+      playlists: false,
+    });
+    await el.updateComplete;
+
+    expect(tabIDs(el)).toEqual(['more']);
+  });
+});

main.go

@@ -6,6 +6,7 @@ import (
 	"log/slog"
 	"os"
 	"strings"
+	"sync/atomic"
 
 	"github.com/golang-cz/devslog"
 	"github.com/wailsapp/wails/v3/pkg/application"
@@ -28,7 +29,61 @@ var (
 //go:embed all:frontend/dist
 var frontendDistAssets embed.FS
 
+// mainStarted latches the first entry into main().
+//
+// **On Android main() is called once per *activity*, and the process
+// outlives the activity.** Wails' JNI entry point is
+// `nativeInit`, which does two things: it re-points the native
+// library's global reference at the calling `WailsBridge`, and it runs
+// `go mainFunc()`. `MainActivity.onCreate` calls it, and Android
+// recreates the activity — for a configuration change it does not
+// declare, under memory pressure, or on every single background when
+// the user has "Don't keep activities" switched on — **without
+// restarting the process**.
+//
+// So main() ran again, on a live app, and every path out of that is
+// fatal:
+//
+//   - `application.New` returns the *existing* `globalApplication` when
+//     there is one, silently discarding the second set of Services.
+//   - `app.Run()` then refuses, by design: `a.starting` is still true,
+//     because Android's `platformRun` is `select{}` and never returns.
+//     It answers "application is running or a previous run has failed".
+//   - which lands on `os.Exit(1)` at the foot of this function, and
+//     that takes down the **first**, perfectly healthy app with it —
+//     its database, its queue, and the audio that a foreground service
+//     is holding the process alive to play.
+//
+// ActivityManager then restarts the app, which is the report: "crashes
+// or restarts when reopened after running in the background". It never
+// left a tombstone because `os.Exit` is not a crash, and it never left
+// a log line because an Android app's fd 1 goes to /dev/null.
+//
+// The latch is the whole fix, and it has to be **first**: everything
+// below it — `NewYellowJacketApp` above all, which opens the SQLite
+// database — is work that must not happen twice in one process.
+// Returning early is not a degraded mode: `nativeInit` has already
+// re-attached the bridge, so the recreated activity's WebView talks to
+// the app that is still running, with its queue and its playback
+// position intact. See CLAUDE.md, "An activity is a view onto the
+// process".
+//
+// It is inert off Android, where a process has exactly one main().
+var mainStarted atomic.Bool
+
+// claimMainOnce reports whether this is the first call to main() in
+// this process. See mainStarted.
+func claimMainOnce() bool {
+	return mainStarted.CompareAndSwap(false, true)
+}
+
 func main() {
+	// Android calls main() once per activity, and the process outlives
+	// the activity. Nothing below this line may run twice.
+	if !claimMainOnce() {
+		return
+	}
+
 	// **Mobile has no home directory, and this must run before anything
 	// asks for a path.** backend/system resolves config and data from
 	// $HOME or the OS equivalent, and on Android there is neither: its

main_test.go

@@ -0,0 +1,104 @@
+package main
+
+import (
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"testing"
+)
+
+// TestMainRunsOncePerProcess pins the latch itself.
+func TestMainRunsOncePerProcess(t *testing.T) {
+	t.Parallel()
+
+	mainStarted.Store(false)
+
+	if !claimMainOnce() {
+		t.Fatal("the first call to claimMainOnce must claim it")
+	}
+
+	if claimMainOnce() {
+		t.Fatal("a second call to claimMainOnce must not claim it: " +
+			"on Android that second call is a second main() in a live " +
+			"process, and every path out of it ends in os.Exit(1)")
+	}
+}
+
+// TestMainClaimsBeforeItDoesAnything is the assertion that actually
+// guards #52, and it is a source sweep for the reason
+// TestNoDirectRuntimeEmits is: no tier here runs main() on Android, so
+// nothing else can see work creeping in above the latch.
+//
+// The failure it exists for is not the latch being deleted — that is
+// loud. It is a line being added above it: a second
+// NewYellowJacketApp opens the SQLite database a second time in one
+// process, and it would do so on every activity recreation, silently,
+// on a build that otherwise looks entirely healthy.
+func TestMainClaimsBeforeItDoesAnything(t *testing.T) {
+	t.Parallel()
+
+	fset := token.NewFileSet()
+
+	file, err := parser.ParseFile(fset, "main.go", nil, 0)
+	if err != nil {
+		t.Fatalf("parse main.go: %v", err)
+	}
+
+	var fn *ast.FuncDecl
+
+	for _, decl := range file.Decls {
+		d, ok := decl.(*ast.FuncDecl)
+		if ok && d.Name.Name == "main" && d.Recv == nil {
+			fn = d
+
+			break
+		}
+	}
+
+	if fn == nil {
+		t.Fatal("no func main in main.go — this test read the wrong file")
+	}
+
+	if len(fn.Body.List) == 0 {
+		t.Fatal("func main is empty")
+	}
+
+	if !claimsMainOnce(fn.Body.List[0]) {
+		t.Fatalf("the first statement of main() must be the "+
+			"`if !claimMainOnce() { return }` guard, got %T — see #52: "+
+			"Android calls main() once per activity, in a process that "+
+			"outlives the activity, so anything above the guard runs "+
+			"again on every recreation", fn.Body.List[0])
+	}
+}
+
+// claimsMainOnce reports whether stmt is `if !claimMainOnce() { return }`.
+func claimsMainOnce(stmt ast.Stmt) bool {
+	ifStmt, ok := stmt.(*ast.IfStmt)
+	if !ok {
+		return false
+	}
+
+	unary, ok := ifStmt.Cond.(*ast.UnaryExpr)
+	if !ok || unary.Op != token.NOT {
+		return false
+	}
+
+	call, ok := unary.X.(*ast.CallExpr)
+	if !ok {
+		return false
+	}
+
+	ident, ok := call.Fun.(*ast.Ident)
+	if !ok || ident.Name != "claimMainOnce" {
+		return false
+	}
+
+	if len(ifStmt.Body.List) != 1 {
+		return false
+	}
+
+	_, ok = ifStmt.Body.List[0].(*ast.ReturnStmt)
+
+	return ok
+}

scripts/android-deploy.sh

@@ -0,0 +1,196 @@
+#!/usr/bin/env bash
+#
+# Install a built APK onto an Android target and launch it, under the
+# package id the APK itself declares.
+#
+# This is the whole body of build/android/Taskfile.yml's four adb-driven
+# tasks — deploy-emulator, run, run:device, deploy-device — which were
+# three lines each, written out four times, and wrong in two ways in all
+# four (#159):
+#
+#   adb uninstall app.yellowjacket    # the RELEASE id, unconditionally
+#   adb install    bin/yellowjacket.apk
+#   adb shell am start -n app.yellowjacket/com.wails.app.MainActivity
+#
+# **The uninstall is not here and does not come back.**  It was there to
+# make the bare `install` on the next line work at all — without -r,
+# Android refuses an install over an existing package — so `install -r`
+# removes the reason for it rather than merely removing it.  What is
+# left is the one case an uninstall really is the remedy, a changed
+# signing certificate, and that is exactly the case where performing it
+# silently costs the user their library.  So it is *named* and not done:
+# an error message carrying the command is a decision the person at the
+# keyboard gets to make, which is the same answer scripts/android-
+# emulator.sh already reached for `make android-install`.
+#
+# **The id is read back from the artifact**, never defaulted, so the
+# thing installed and the thing launched cannot disagree — see
+# scripts/android-pkgid.sh for why that is by construction rather than
+# by discipline.
+#
+# **The target is checked against the task's own name.**  The emulator
+# tasks used a bare `adb`, which with one device attached picks that
+# device whatever it is — so `wails3 task android:run`, whose summary
+# says "in the Android Emulator", installed on the phone when a phone
+# was the only thing plugged in.  A task addressing something other than
+# what it says is the same fault as the package id, one level up.
+#
+# Usage:
+#   android-deploy.sh --apk <path> --target emulator|device|any \
+#                     [--expect <id>] [--serial <s>] [--no-launch]
+set -euo pipefail
+
+cd "$(dirname "$0")/.."
+
+SDK="${ANDROID_HOME:-${ANDROID_SDK_ROOT:-$HOME/Android/Sdk}}"
+ADB="$(command -v adb || echo "$SDK/platform-tools/adb")"
+
+# **Not "$PKG/.MainActivity".**  A leading-dot activity is resolved
+# against the applicationId, and the scaffold's activity lives in the
+# Java package com.wails.app, which is deliberately not it.  The short
+# form fails with a class-not-found that reads like a broken build.
+ACTIVITY="${YJ_ANDROID_ACTIVITY:-com.wails.app.MainActivity}"
+
+APK=""
+TARGET="any"
+EXPECT=""
+SERIAL="${ANDROID_SERIAL:-${DEVICE_ID:-}}"
+LAUNCH=1
+
+die() { echo "android-deploy: $*" >&2; exit 1; }
+
+while [ $# -gt 0 ]; do
+	case "$1" in
+	--apk) APK="${2:-}"; shift 2 ;;
+	--target) TARGET="${2:-}"; shift 2 ;;
+	--expect) EXPECT="${2:-}"; shift 2 ;;
+	--serial) SERIAL="${2:-}"; shift 2 ;;
+	--no-launch) LAUNCH=0; shift ;;
+	*) die "unknown option $1" ;;
+	esac
+done
+
+[ -n "$APK" ] || die "--apk is required"
+[ -f "$APK" ] || die "no such APK: $APK
+    Build one first:  wails3 task android:assemble:apk   (debug)
+                      wails3 task android:package        (release)"
+[ -x "$ADB" ] || command -v adb >/dev/null ||
+	die "adb not found. Install the Android SDK platform-tools (or set ANDROID_HOME)"
+
+case "$TARGET" in
+emulator | device | any) ;;
+*) die "--target must be emulator, device or any (got '$TARGET')" ;;
+esac
+
+# ---------------------------------------------------------------- #
+# Which package
+# ---------------------------------------------------------------- #
+
+# This runs *before* a target is chosen, deliberately: the guard is a
+# question about the artifact, so it can be answered — and exercised —
+# with nothing plugged in, and a build whose id is wrong should be
+# refused whether or not there is anything to install it onto.
+#
+# An unreadable APK, or an id that is not the one the caller named, is a
+# hard stop before anything is installed or launched.  Spelled as two
+# calls rather than one with a conditional argument: an empty array under
+# `set -u` is an unbound variable in bash 3.2, which is what macOS ships.
+if [ -n "$EXPECT" ]; then
+	PKG="$(./scripts/android-pkgid.sh "$APK" --expect "$EXPECT")"
+else
+	PKG="$(./scripts/android-pkgid.sh "$APK")"
+fi
+
+# ---------------------------------------------------------------- #
+# Which target
+# ---------------------------------------------------------------- #
+
+# An emulator serial is "emulator-<port>"; anything else online is a
+# physical device.  That is the same test the device tasks already made,
+# and the emulator tasks did not make at all.
+online_matching() {
+	case "$TARGET" in
+	emulator) "$ADB" devices | awk 'NR > 1 && $2 == "device" && $1 ~ /^emulator-/ { print $1 }' ;;
+	device) "$ADB" devices | awk 'NR > 1 && $2 == "device" && $1 !~ /^emulator-/ { print $1 }' ;;
+	any) "$ADB" devices | awk 'NR > 1 && $2 == "device" { print $1 }' ;;
+	esac
+}
+
+if [ -z "$SERIAL" ]; then
+	matches="$(online_matching)"
+	count="$(printf '%s' "$matches" | grep -c . || true)"
+
+	if [ "$count" -eq 0 ]; then
+		echo "android-deploy: no ${TARGET/any/attached} target is online." >&2
+		"$ADB" devices | sed '1d;/^$/d;s/^/    /' >&2 || true
+		if [ "$TARGET" = "emulator" ]; then
+			echo "    Start one with:  make android-emulator" >&2
+		elif [ "$TARGET" = "device" ]; then
+			echo "    Plug a phone in and authorise the adb key." >&2
+		fi
+		exit 1
+	fi
+
+	# Several is ambiguous, and picking the first silently is how a
+	# build lands on a target nobody named.  The old run:device did
+	# exactly that.
+	if [ "$count" -gt 1 ]; then
+		echo "android-deploy: several $TARGET targets are online — name one." >&2
+		printf '%s\n' "$matches" | sed 's/^/    /' >&2
+		echo "    Pass DEVICE_ID=<serial>, or set ANDROID_SERIAL." >&2
+		exit 1
+	fi
+
+	SERIAL="$matches"
+fi
+
+# ---------------------------------------------------------------- #
+# Install
+# ---------------------------------------------------------------- #
+
+echo "android-deploy: $APK ($PKG) -> $SERIAL"
+
+if ! out="$("$ADB" -s "$SERIAL" install -r "$APK" 2>&1)"; then
+	printf '%s\n' "$out"
+	case "$out" in
+	*INSTALL_FAILED_UPDATE_INCOMPATIBLE* | *"signatures do not match"*)
+		cat >&2 <<EOF
+
+The copy of $PKG already installed was signed with a different key, and
+Android never allows that as an update.
+
+The only way forward is an uninstall — **which deletes that app's data**,
+and for this app that is the user's library, irreversibly.  So it is not
+done for you.  If the installed copy is disposable:
+
+    $ADB -s $SERIAL uninstall $PKG
+
+If it is not — if this is a released build with a real library on it —
+install the debug variant instead, which carries applicationIdSuffix
+".dev" and so sits beside it rather than replacing it:
+
+    wails3 task android:assemble:apk
+EOF
+		;;
+	*INSTALL_FAILED_VERSION_DOWNGRADE*)
+		cat >&2 <<EOF
+
+The installed copy of $PKG has a higher versionCode than this build.
+A bare 'make android' builds versionCode 1; a versioned one builds e.g.
+10301.  Either build with a version:
+
+    YJ_VERSION=1.3.1 YJ_VERSION_CODE=10301 make android
+
+or, if the installed copy is disposable, remove it:
+
+    $ADB -s $SERIAL uninstall $PKG
+EOF
+		;;
+	esac
+	exit 1
+fi
+printf '%s\n' "$out"
+
+[ "$LAUNCH" -eq 1 ] || exit 0
+
+"$ADB" -s "$SERIAL" shell am start -n "$PKG/$ACTIVITY"

scripts/android-emulator.sh

@@ -34,7 +34,21 @@ cd "$(dirname "$0")/.."
 
 AVD="${YJ_AVD:-yj-test}"
 SDK="${ANDROID_SDK_ROOT:-${ANDROID_HOME:-$HOME/Android/Sdk}}"
-PKG="${YJ_ANDROID_PKG:-app.yellowjacket}"
+# The third declaration of the app's identity, and the one #159 did not
+# cash out in -- but the same hazard, so it is derived rather than
+# written down too. The APK in bin/ is what `make android-install` is
+# about to install and what `android-launch`, `logs` and `smoke` are
+# about to address, so it is the authority; whatever Gradle resolved the
+# applicationId to, suffix included, is in the file.
+#
+# The literal survives only as the answer for a tree with no APK built
+# yet, where these commands are asking about whatever is already on the
+# device and there is nothing to read. YJ_ANDROID_PKG still overrides.
+PKG="${YJ_ANDROID_PKG:-}"
+if [ -z "$PKG" ] && [ -f bin/yellowjacket.apk ]; then
+	PKG="$(./scripts/android-pkgid.sh bin/yellowjacket.apk 2>/dev/null || true)"
+fi
+PKG="${PKG:-app.yellowjacket}"
 # Where `make android-inspect` forwards the WebView's devtools socket.
 CDP_PORT="${YJ_ANDROID_CDP_PORT:-9222}"
 # **Not "$PKG/.MainActivity".** A leading-dot activity is resolved
@@ -281,15 +295,24 @@ cmd_inspect() {
 	need_sdk
 	pick_device || die "no device -- plug a phone in (USB debugging on) or run 'make android-emulator'"
 
-	local pkg pid
+	local pkg pid candidates
 	pid=""
 
-	for pkg in "$PKG.dev" "$PKG"; do
+	# Debug sibling first, release second, whichever way round $PKG was
+	# resolved -- it is read from the built APK now, so it is already the
+	# .dev id whenever a debug build is what is in bin/, and appending a
+	# second ".dev" to it would probe a package that cannot exist.
+	case "$PKG" in
+	*.dev) candidates="$PKG ${PKG%.dev}" ;;
+	*) candidates="$PKG.dev $PKG" ;;
+	esac
+
+	for pkg in $candidates; do
 		pid=$("$ADB" shell pidof "$pkg" 2>/dev/null | tr -d '\r' | awk '{print $1}')
 		[ -n "$pid" ] && break
 	done
 
-	[ -n "$pid" ] || die "neither $PKG.dev nor $PKG is running; launch it first"
+	[ -n "$pid" ] || die "none of: $candidates is running; launch it first"
 
 	"$ADB" forward --remove-all >/dev/null 2>&1 || true
 	"$ADB" forward "tcp:$CDP_PORT" "localabstract:webview_devtools_remote_$pid" >/dev/null \

scripts/android-pkgid.sh

@@ -0,0 +1,97 @@
+#!/usr/bin/env bash
+#
+# Print the package id an APK actually declares — and, given --expect,
+# refuse when that is not the id the caller was about to act on.
+#
+# This exists because the identity is declared twice and nothing made
+# the two agree.  `applicationId` in build/android/app/build.gradle is
+# what Gradle installs; `APP_ID` in build/android/Taskfile.yml was what
+# every adb-driven task uninstalled, launched and filtered.  They differ
+# for a reason nobody has to get wrong: the debug buildType carries
+# `applicationIdSuffix ".dev"`, so a debug build is app.yellowjacket.dev
+# while the default was app.yellowjacket — the *release* id, and on a
+# real phone the released app with the user's library on it (#159).
+#
+# So the id is read back from the artifact rather than written down a
+# third time.  The APK is the authority because the task that installs
+# it has just built it: whatever Gradle resolved the applicationId to,
+# suffixes and flavours included, is in the file, and no default can
+# disagree with it.
+#
+# Usage:
+#   android-pkgid.sh <apk> [--expect <id>]
+#
+# Exit codes: 0 printed the id; 1 could not read it; 2 --expect failed.
+set -euo pipefail
+
+die() { echo "android-pkgid: $*" >&2; exit 1; }
+
+APK=""
+EXPECT=""
+while [ $# -gt 0 ]; do
+	case "$1" in
+	--expect) EXPECT="${2:-}"; shift 2 ;;
+	-*) die "unknown option $1" ;;
+	*) APK="$1"; shift ;;
+	esac
+done
+
+[ -n "$APK" ] || die "usage: android-pkgid.sh <apk> [--expect <id>]"
+[ -f "$APK" ] || die "no such APK: $APK"
+
+# aapt2 lives under build-tools/<version>/, which is versioned, so it is
+# resolved rather than pinned.  PATH first, so a system aapt2 (Arch ships
+# one) works without an SDK layout at all.
+find_aapt() {
+	local sdk name
+	for name in "$@"; do
+		command -v "$name" 2>/dev/null && return 0
+	done
+	sdk="${ANDROID_HOME:-${ANDROID_SDK_ROOT:-$HOME/Android/Sdk}}"
+	for name in "$@"; do
+		ls "$sdk"/build-tools/*/"$name" 2>/dev/null | sort -V | tail -1 | grep . && return 0
+	done
+	return 1
+}
+
+pkg=""
+
+# `aapt2 dump packagename` answers in one word and is the cheapest of
+# the three.  aapt1 is the fallback because it is what older build-tools
+# carry and what the issue's own measurement used.
+if AAPT2="$(find_aapt aapt2)"; then
+	pkg="$("$AAPT2" dump packagename "$APK" 2>/dev/null | head -1 | tr -d '\r')" || true
+fi
+
+if [ -z "$pkg" ] && AAPT="$(find_aapt aapt)"; then
+	pkg="$("$AAPT" dump badging "$APK" 2>/dev/null |
+		sed -n "s/^package: name='\([^']*\)'.*/\1/p" | head -1)" || true
+fi
+
+# Guessing here is the bug this file exists to prevent, so an unreadable
+# APK is a hard failure and never a fallback to a written-down default.
+if [ -z "$pkg" ]; then
+	die "could not read a package name from $APK.
+    Install the SDK build-tools (aapt2), or set ANDROID_HOME to an SDK
+    that carries them:  sdkmanager 'build-tools;34.0.0'"
+fi
+
+if [ -n "$EXPECT" ] && [ "$EXPECT" != "$pkg" ]; then
+	cat >&2 <<EOF
+android-pkgid: refusing to act on a package this APK does not declare.
+
+    the APK declares:  $pkg
+    the task expects:  $EXPECT
+    APK:               $APK
+
+These must agree, and when they do not it is the *expectation* that is
+wrong: the APK is what Gradle built.  A debug build carries
+applicationIdSuffix ".dev" (app/build.gradle), so a task that assembles
+a debug APK and then addresses the unsuffixed id is addressing the
+released app — which on a real device is the user's install, with their
+library in it (#159).
+EOF
+	exit 2
+fi
+
+printf '%s\n' "$pkg"