docs(jobs): the phone's band, and why it is in flow

CLAUDE.md's jobs section said the header indicator is "the one view of
everything at once, from every page"; that is now true on a desktop
only, and the band is the phone's half.

NOTES.md takes the measurement that decided the shape -- an overlay
band at 424x439 is a lid, not a notification -- and the corollary about
which tier can see it: ui-test, tsc, lint and the Go suite all passed
on the broken version, and what failed was three e2e specs that have
nothing to do with jobs. Run the suite, not the spec you wrote.

.planning/NOTES.md

@@ -4302,3 +4302,51 @@ compiles against HEAD with a single shim
 (`SetPlaybackFinishedHandler` gained a `srcErr error` parameter), which
 makes "did the backend fix cause this" a ten-minute question instead of
 a full checkout.
+
+## An overlay band is not a notification, it is a lid (measured 2026-08-20)
+
+#62 asks for background jobs to become "a notification" on the phone,
+and the app has exactly one notification surface, so the first version
+of the fix put `<job-panel>` in `notification-host`'s band — which is
+`position: fixed` under the header. It renders correctly, it is on top,
+it is inside the viewport, and it is unusable.
+
+At the device's 424x439 viewport a **compact** panel showing two active
+jobs is ~216px — half the screen — drawn over the content, with
+`pointer-events: auto` so it swallows every tap underneath. Nothing in
+the component tier could see it. The e2e suite could: four specs failed,
+and *none* of them was about jobs — two `phone-shell` journeys into the
+full-screen Now Playing and `header-action-overflow`'s phone case, all
+three because the band was intercepting taps meant for the app.
+
+`<job-band>` is in the shell's grid instead, as a row between the top
+bar and the main panel, so it **pushes**. That is #24's one sentence
+("no action is ever unreachable at any supported size") deciding a
+layout question: a band that hides the app in order to say the app is
+busy has traded the popover's fault for a worse one.
+
+Two things fell out of it worth keeping:
+
+- **A finished row in flow is furniture.** The overlay could afford to
+  keep terminal jobs around; a row that holds the content down after
+  the work is done cannot. `job-panel` grew `active-only` for the band,
+  and Settings keeps finished rows because that is where "did the last
+  scan work" is asked.
+- **`job-row` already had the right density.** `variant="compact"` is
+  described in its own source as "the popover density", which is
+  exactly what the band is replacing — 216px against 259px for the
+  same two jobs, and no per-job statistics that a phone has no room
+  for.
+
+## The e2e suite is the tier that sees a shell regression (2026-08-20)
+
+Worth stating because it decided how #62 was verified. The change is
+one component, one stylesheet and one line of `index.html`; `make
+ui-test` (955 tests) passed on the broken overlay version and so did
+`tsc`, `lint` and the whole Go suite. The failure was three specs that
+have nothing to do with jobs, failing on `click()` timeouts.
+
+The corollary for anything that draws over the shell: **run the whole
+e2e suite, not the spec you wrote.** A spec written for a feature
+asserts the feature works; what a new overlay breaks is everything
+else, and only the suite is looking at that.