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/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:run:device       # debug build + install + launch on a phone
-wails3 task android:deploy-device    # production APK to a device
+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
+installs; `APP_ID` in `build/android/Taskfile.yml` was what every
-adb-driven task uninstalls, launches and filters. **Nothing enforces
+adb-driven task uninstalled, launched and filtered, and nothing
-that they agree**, and `ANDROID.md`'s advice to set `APP_ID` in
+enforced that they agree. They did not: the debug buildType carries
-`build/config.yml` does not work in beta.8 — `wails3 task` never reads
+`applicationIdSuffix ".dev"`, so every task that assembles a debug APK
-that file (verified with `--dry`), and even when set it feeds only the
+addressed the release id. This file flagged the hazard for five phases
-adb commands, never Gradle. Change both or the official `run`/`deploy`
+and it cashed out twice — once as a wrong `am start`, once as an
-tasks address a package that is not installed.
+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

@@ -3891,3 +3891,354 @@ 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
@@ -1572,6 +1626,50 @@ 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

@@ -666,6 +666,49 @@ 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

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

@@ -54,6 +54,16 @@ type GeneralConfig struct {
 	// 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.

build/android/Taskfile.yml

@@ -4,18 +4,28 @@ includes:
   common: ../Taskfile.yml
 
 vars:
-  # The *installed* package name, which every adb-driven task below uses
+  # APP_ID is an *assertion*, not a setting, and it has no default.
-  # to uninstall, launch and filter. It must agree with `applicationId`
-  # in app/build.gradle, and nothing enforces that.
   #
-  # ANDROID.md says to set this in build/config.yml. That does not work
+  # It used to be the id every adb-driven task below uninstalled,
-  # in beta.8, checked both ways: `wails3 task` builds its var set from
+  # launched and filtered, defaulting to "app.yellowjacket". It could
-  # CLI KEY=VALUE arguments and the Taskfile tree only -- nothing reads
+  # never have been a setting: `wails3 task` builds its var set from CLI
-  # config.yml -- and even when set it feeds only these adb commands,
+  # KEY=VALUE arguments and the Taskfile tree only -- nothing reads
-  # never Gradle. So the identity is declared twice, here and in
+  # build/config.yml, contrary to ANDROID.md, checked with --dry -- and
-  # build.gradle, and a change to one alone means the official run and
+  # even when set it fed only the adb commands, never Gradle. So the
-  # deploy tasks address a package that is not installed.
+  # identity was declared twice, here and as `applicationId` in
-  APP_ID: '{{.APP_ID | default "app.yellowjacket"}}'
+  # 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'
+      - './scripts/android-deploy.sh --apk "{{.BIN_DIR}}/{{.APP_NAME}}.apk" --target emulator{{if .APP_ID}} --expect "{{.APP_ID}}"{{end}}'
-      - '"{{.ADB}}" install "{{.BIN_DIR}}/{{.APP_NAME}}.apk"'
-      - '"{{.ADB}}" shell am start -n {{.APP_ID}}/com.wails.app.MainActivity'
 
   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'
+      - './scripts/android-deploy.sh --apk "{{.BIN_DIR}}/{{.APP_NAME}}.apk" --target emulator{{if .APP_ID}} --expect "{{.APP_ID}}"{{end}}'
-      - '"{{.ADB}}" install "{{.BIN_DIR}}/{{.APP_NAME}}.apk"'
-      - '"{{.ADB}}" shell am start -n {{.APP_ID}}/com.wails.app.MainActivity'
 
   device:list:
     summary: Lists connected Android devices and emulators (serials)
@@ -400,25 +406,7 @@ tasks:
           ARCH: arm64
     cmds:
       - task: assemble:apk
-      - |
+      - './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}}'
-        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
     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:
-      - |
+      - './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}}'
-        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
     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
+      // The container has to be a scroller at all, which is the thing
-      // "scrollable at all" (#133). The guard used to be
+      // the defect behind this spec broke and is a property rather
-      // `scrollHeight > clientHeight + 40` while the next line asks to
+      // than a moment.
-      // 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.
       await expect
         .poll(() => scrollRange(app))
-        .toMatchObject({ room: true, overflowY: 'auto' });
+        .toMatchObject({ overflowY: 'auto' });
 
-      await app.evaluate((target) => {
+      // **Scrolling it and reading it back are one round trip** (#151).
-        const sc = document
+      //
-          .querySelector('cover-grid')
+      // #133 made the guard ask for the range this needs rather than
-          ?.shadowRoot?.querySelector('.grid-scroll-container');
+      // for "scrollable at all", which was necessary and is not
-
+      // sufficient: a guard and the write it guards are separate
-        if (sc) sc.scrollTop = target;
+      // `evaluate` calls, so the grid can satisfy the range and settle
-      }, SCROLL_TARGET);
+      // out of it before the write lands. It still does — observed as
-
+      // `Expected 80, Received 10` in the second of three consecutive
-      expect(await scrollTop(app)).toBe(SCROLL_TARGET);
+      // 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:
+      // Reported for the failure message rather than waited on: `room`
-      // enough range to actually reach the target. A threshold below
+      // was the guard #133 strengthened, and #151 is that a guard in
-      // what the caller depends on is not a guard.
+      // 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(
+ * Scroll the grid and report where it actually landed, in one call.
-    () =>
+ *
-      document
+ * The whole point is that the set and the read share a moment: a
-        .querySelector('cover-grid')
+ * `scrollTop` write is clamped to the range *at the instant it lands*,
-        ?.shadowRoot?.querySelector('.grid-scroll-container')?.scrollTop ?? -1,
+ * 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');
+
+    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
+    // No disclosure to open first, and no state to put back afterwards:
-    // queue panel renders no list — so this has to open it first.
+    // #42 made the slider inline, so it is simply there. The assertion
-    await app.getByRole('button', { name: /volume/i }).click();
+    // 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/layout-overflow.spec.ts

@@ -132,22 +132,34 @@ 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) => {
+    //
-      const settings = el.shadowRoot?.querySelector<HTMLElement>(
+    // The scroll and the measurement share one `evaluate` — #151's
-        '[data-testid="nav-settings"]',
+    // 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"]',
+          );
 
-      if (!settings) return null;
+          if (!settings) return null;
 
-      el.scrollTop = el.scrollHeight;
+          el.scrollTop = el.scrollHeight;
 
-      const item = settings.getBoundingClientRect();
+          const item = settings.getBoundingClientRect();
-      const pane = el.getBoundingClientRect();
+          const pane = el.getBoundingClientRect();
 
-      return item.bottom <= Math.ceil(pane.bottom) && item.top >= Math.floor(pane.top);
+          return (
-    });
+            item.bottom <= Math.ceil(pane.bottom) &&
-
+            item.top >= Math.floor(pane.top)
-    expect(reachable).toBe(true);
+          );
+        }),
+      )
+      .toBe(true);
   });
 });
 

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
+    // is not a thumb target -- both belong to the full-screen
-    // full-screen now-playing view.
+    // now-playing view.
-    await expect(app.locator('audio-player volume-control')).toBeHidden();
+    //
+    // `.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

@@ -93,10 +93,31 @@ async function queueSixAndOpen(app: Page): Promise<void> {
       'library.Library.GetTracks',
       [0],
       10_000,
-    )) as { FilePath: string; TrackName: string }[];
+    )) as { FilePath: string; TrackName: string; Album: string }[];
 
     const long = tracks.find((t) => t.TrackName === longTitle);
-    const rest = tracks.filter((t) => t.TrackName !== longTitle).slice(0, 5);
+
+    /**
+     * **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.
@@ -223,7 +244,14 @@ test.describe('selecting in the queue with a mouse', () => {
       .poll(() => selected(app), { timeout: HIGHLIGHT_MS })
       .toEqual([1]);
 
-    await row(app, 2).locator('.explore-link').first().click();
+    // `.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',

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.
@@ -207,6 +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.
  */

frontend/index.css

@@ -211,7 +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;
 
@@ -239,23 +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;
@@ -440,6 +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;
@@ -448,4 +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

@@ -40,16 +40,31 @@
         </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>
-        <button aria-label="Toggle queue" aria-controls="queue-panel" aria-expanded="false"
+        <div class="bar-end">
-            id="queue-button">
+            <volume-control></volume-control>
-            <!-- ICON_QUEUE in src/utils/icon-language.ts, written out
+            <button aria-label="Toggle queue" aria-controls="queue-panel" aria-expanded="false"
-                 because this file has no module scope. It was `list`,
+                id="queue-button">
-                 which is the Playlists destination's icon. -->
+                <!-- ICON_QUEUE in src/utils/icon-language.ts, written out
-            <wa-icon name="bars-staggered"></wa-icon>
+                     because this file has no module scope. It was `list`,
-        </button>
+                     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';

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);
   }
@@ -154,10 +196,12 @@ export class VolumeControl extends LitElement {
   private handleOutsideClick(e: Event) {
     const path = e.composedPath();
 
-    if (!path.includes(this)) {
+    if (!path.includes(this)) this.closeSlider();
-      this.showSlider = false;
+  }
-      document.removeEventListener('click', this.boundHandleOutsideClick);
+
-    }
+  private closeSlider() {
+    this.showSlider = false;
+    document.removeEventListener('click', this.boundHandleOutsideClick);
   }
 
   private handleInput(e: Event) {
@@ -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/config-page/config-page.ts

@@ -25,6 +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';
@@ -125,6 +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
@@ -938,20 +942,28 @@ export class ConfigPage extends ViewLifecycleMixin(LitElement) {
 
     private async loadLibraries(): Promise<void> {
         try {
-            const [libs, mode, defaultPage, queueFallback, allowMetered] =
+            const [
-                await Promise.all([
+                libs,
-                    GetAllLibrariesWithTrackCounts(),
+                mode,
-                    GetScanConcurrency(),
+                defaultPage,
-                    GetDefaultPage(),
+                queueFallback,
-                    GetQueueFallback(),
+                allowMetered,
-                    GetAllowMeteredCatalogDownload(),
+                popupVolume,
-                ]);
+            ] = await Promise.all([
+                GetAllLibrariesWithTrackCounts(),
+                GetScanConcurrency(),
+                GetDefaultPage(),
+                GetQueueFallback(),
+                GetAllowMeteredCatalogDownload(),
+                GetPopupVolume(),
+            ]);
 
             this.libraries = libs ?? [];
             this.concurrencyMode = mode;
             this.defaultPage = defaultPage;
             this.queueFallback = queueFallback;
             this.allowMeteredCatalogDownload = allowMetered;
+            this.popupVolume = popupVolume;
 
         } catch (err) {
             console.error(
@@ -1858,10 +1870,51 @@ 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 ---
 
     /**

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/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/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');
   });
 });

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"