refactor(player): E.42 — migrate playerStore re-exports to direct imports (#607)

Migrates ~74 call sites away from the playerStore re-export shims that
were kept during M0–E.41 to avoid touching 30+ imports per PR. Now
that the bigger refactor work is done, each helper goes back to its
real home:

- `initAudioListeners`, `installQueueUndoHotkey`, `flushPlayQueuePosition`
  → from their own store modules
- `getPlaybackProgressSnapshot`, `subscribePlaybackProgress`,
  `PlaybackProgressSnapshot` → from `playbackProgress`
- `resolveReplayGainDb`, `shuffleArray`, `songToTrack`
  → from `utils/*`
- `_resetQueueUndoStacksForTest`, `consumePendingQueueListScrollTop`,
  `registerQueueListScrollTopReader` → from `queueUndo`
- `PlayerState`, `Track` types → from `playerStoreTypes`

Drops the corresponding 13 re-export stubs from `playerStore.ts` and
the now-unused imports. Also drops dead section banners + per-wrapper
comments above one-line action delegates. Trims one stale "(separate
PR)" note in `transportLightActions.ts` since that follow-up landed
in E.39.

`playerStore.ts`: 180 → 112 LOC (−68). Down from Phase E's starting
3732 LOC.

`bootstrap.test.ts` mock target updated from `../store/playerStore`
to `../store/queueUndoHotkey` to keep the spy reachable after the
import change.

src/utils/buildInfiniteQueueCandidates.ts

@@ -1,3 +1,4 @@
+import type { Track } from '../store/playerStoreTypes';
 import { getRandomSongs, getSimilarSongs2, getTopSongs } from '../api/subsonic';
 import {
   enrichSongsForMixRatingFilter,
@@ -6,8 +7,6 @@ import {
 } from './mixRatingFilter';
 import { shuffleArray } from './shuffleArray';
 import { songToTrack } from './songToTrack';
-import type { Track } from '../store/playerStore';
-
 /**
  * Infinite queue source strategy (Instant Mix-like):
  * 1) Prefer artist-driven candidates (Top + Similar) around the current track.