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/store/playerStore.progress.test.ts

@@ -10,6 +10,8 @@
  * Drive emits via the `audio:progress` Tauri event (the only public path
  * to `emitPlaybackProgress`).
  */
+import { initAudioListeners } from './initAudioListeners';
+import { getPlaybackProgressSnapshot, subscribePlaybackProgress, type PlaybackProgressSnapshot } from './playbackProgress';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 
 vi.mock('@/api/subsonic', async () => {
@@ -36,13 +38,7 @@ vi.mock('@/api/lastfm', () => ({
   lastfmGetAllLovedTracks: vi.fn(async () => []),
 }));
 
-import {
-  getPlaybackProgressSnapshot,
-  initAudioListeners,
-  subscribePlaybackProgress,
-  usePlayerStore,
-  type PlaybackProgressSnapshot,
-} from './playerStore';
+import { usePlayerStore } from './playerStore';
 import { emitTauriEvent, onInvoke } from '@/test/mocks/tauri';
 import { resetPlayerStore, resetAuthStore } from '@/test/helpers/storeReset';
 import { makeTrack } from '@/test/helpers/factories';