Keep the Glass Stage notes toolbar on one row at every player width

docs/glass-stage-iphone-followup.md

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+# Glass Stage iPhone layout follow-up
+
+The supplied production screenshots came from build `16c08b099a31`, before the
+Task A/B changes. This follow-up preserves the Glass Stage colours, glass tiles,
+stroke icons and all existing control ids/actions. Every CSS rule is scoped to
+`html[data-layout="glass-stage"]`; Classic retains its original rail and labels.
+
+## Panel shortcuts and bottom chrome
+
+The Glass section rail was a fixed horizontal overlay positioned above the mini
+player. Clearing the player did not clear a panel heading or filter underneath.
+`glass-panel-layout.js` moves that same rail, with its existing listeners, into
+`#listPane` before the heading. It restores the original location when leaving
+Glass Stage. The rail now occupies its own row instead of covering content.
+
+The module measures the visible fixed bottom navigation and mini player. The
+navigation's measured height already contains the home-indicator safe area;
+the mini player sits eight pixels above that height. Scroll clearance includes
+both bars and a 16 px gap, without counting the safe area twice. Portrait uses
+one shared scroller and reserves that clearance once at its tail; desktop panes
+reserve it individually. The mini player's outer card clips the progress strip
+inside its rounded border, rather than leaving a separate line below it.
+
+## Bottom navigation
+
+The uploaded rightward icon shift is reproduced by the pre-Task-A CSS from
+`f2c9459`: installed-PWA padding of `4px 16px` remained on a fixed-width icon box.
+Task A (`79a3c28`) already resets that padding to zero. The new regression test
+runs an iPhone 13 browser profile at 390 px, including 34 px bottom safe-area
+allowance, Queue/Downloads badges and an active pill. In both Chromium and
+WebKit, SVG and icon-box centres match label centres within 0.6 CSS px. The old
+CSS shifts every icon more than eight CSS px. No further nav CSS change was
+needed; this is committed verification of the existing fix.
+
+## Notes toolbar
+
+The toolbar's Glass override explicitly enabled `flex-wrap:wrap`. It now keeps
+one row. Container queries respond to the player card's available width, even
+when a desktop player column is narrow. Spacing tightens first, the longer
+Chapters & bookmarks label becomes icon/count at narrow card widths, and all
+labels become icon-only on the smallest cards. Full accessible names and title
+hints remain. Every action retains a minimum 44 px target, and the fold chevron
+stays at the row's right end. Status text truncates within the remaining space.
+Glass label wrappers and added names restore exactly when switching to Classic.
+
+## Verification
+
+- 125 frontend unit tests pass, including measured chrome-clearance logic.
+- `node --check frontend/app.js` and `bun build --no-bundle server/server.js` pass.
+- Chromium and WebKit: all five panel shortcuts at 390 and 1440 px; final list
+  row clears playback chrome; progress strip stays inside its card.
+- Classic geometry and before/after screenshot comparisons pass in both browsers
+  at 390 and 1440 px, within the 32-pixel isolated rasterization tolerance.
+- iPhone-profile navigation alignment/badges pass in both engines at 390 px.
+- Toolbar stays one row at 320, 360, 390, 430 and 1440 px in both engines, including
+  long status text and chapter counts; theme round-trip restoration passes.
+- Batched visual review of six WebKit captures found no overlap, alignment,
+  clipping or wrapping defects in the requested areas.
+
+Run `npx playwright test -c playwright.glass-panel.config.js` for the 22 browser
+cases. WebKit was installed locally for these checks; these are browser/iPhone
+profile tests, not tests on physical iPhone hardware. Review the installed PWA
+on an actual iPhone after the reviewer deploys, particularly when the mini
+player appears/disappears and after rotating the phone.
+
+Before/after captures are saved under
+`/home/josh/deliverables/ytplayer-done9/`. No push or deployment was performed.