feat: wall-clock clip labels, collapsible day Highlights with analysed marker

- Clip bar label is now the wall-clock time of occurrence plus queue
  position ("03:46:20 to 03:46:22 (73 / 187)"); filename and score moved
  to the hover tooltip. Works for both per-file and day queues via an
  absStart epoch on every queue entry, derived from the filename clock
  (listing date), falling back to in-file offsets for non-standard names.
- Day Highlights button toggles the panel; re-expanding reuses the
  already-built results (re-armed J/K queue from dayHlSections) and only
  recomputes when margin/gap/min-duration changed. A "analysed" suffix
  marks days where every file has a cached analysis for the current
  params; fetchAnalysis keeps f.cached_analysis fresh client-side.
- Day timeline now positions files by the filename clock instead of
  mtime-duration, and the three axis labels (span start / midpoint /
  end) carry explanatory tooltips.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

CLAUDE.md

@@ -38,8 +38,8 @@ Dependencies: `requests` (streams), `numpy` + `soundfile` (FLAC output and FLAC
 - Serving: `_stream()` (Range support), `_copy_to_response()`, `_safe_path()` (path traversal guard).
 
 `webui.html` (one `<script>` block):
-- Clip review: `clipQueue`/`clipCursor` globals, `playClip()`, `playFileSection()`, `hideClipBar()`; markup is the `#clip-bar` div.
-- Day review: `dayHighlights()` builds `dayActiveSections` (chronological); `jumpToDaySection()` arms the queue.
+- Clip review: `clipQueue`/`clipCursor` globals, `playClip()`, `playFileSection()`, `hideClipBar()`; markup is the `#clip-bar` div. The clip label shows the wall-clock occurrence time + queue position (`03:46:20 to 03:46:22 (73 / 187)`): queue entries carry `absStart` (epoch s), derived from `fileStartEpoch(f.date)` — the filename clock — with in-file offsets as fallback for non-standard names; filename/score live in the label tooltip.
+- Day review: `dayHighlights()` builds `dayActiveSections` (chronological); `jumpToDaySection()` arms the queue. The day timeline positions files by `fileStartEpoch(f.date)` (filename clock), mtime−duration only as fallback. The Highlights button is a collapse/expand toggle (`setHlExpanded()` keeps arrow + `aria-expanded` in sync, also from the day-collapse path): a built panel is kept and re-armed from `dayHlSections` instead of recomputing, keyed by `hlRow.dataset.loaded = hlParams()` (margin|gap|minDur string) so changed params force a re-run. The `#dayhls-<dayId>` "· analysed" suffix appears when every file's `cached_analysis` passes `cachedParamsMatch()`; `fetchAnalysis()` updates `f.cached_analysis` client-side so the marker survives re-renders without refetching `/api/files`.
 - J/K/U/I/O: single document-level `keydown` listener — clip queue takes priority, in-player `currentTime` stepping is the fallback when no queue is armed; O calls `openClipInFile()` (shared with the "Open in file" button). U/I (and the `#clip-hl-only` checkbox, which also affects J/K, Prev/Next, and auto-advance) restrict stepping to highlights: the top `#clip-top` (default 50) sections by score, computed on demand by `topScoreSet()`; `stepClip()` is the shared queue-stepping path.
 - Analysis: `fetchAnalysis()` (session `analysisCache`), `analyse()` (per-row render), `cachedParamsMatch()` (autoload guard).