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/test/helpers/factories.ts

@@ -5,7 +5,7 @@
  * the fields the test cares about. Keeps tests focused on behaviour rather
  * than on assembling boilerplate.
  */
-import type { Track } from '@/store/playerStore';
+import type { Track } from '@/store/playerStoreTypes';
 import type { ServerProfile } from '@/store/authStore';
 import type { SubsonicSong } from '@/api/subsonic';
 

src/test/helpers/storeReset.ts

@@ -20,7 +20,8 @@
  *   // or for cross-store tests:
  *   beforeEach(resetAllStores);
  */
-import { usePlayerStore, _resetQueueUndoStacksForTest } from '@/store/playerStore';
+import { _resetQueueUndoStacksForTest } from '@/store/queueUndo';
+import { usePlayerStore } from '@/store/playerStore';
 import { useAuthStore } from '@/store/authStore';
 import { usePreviewStore } from '@/store/previewStore';
 import { useOrbitStore } from '@/store/orbitStore';