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/uiStateActions.ts

@@ -8,13 +8,8 @@ type SetState = (
 ) => void;
 
 /**
- * Pure-UI state setters that mutate playerStore fields with no audio
- * engine / network side effects: starred + rating optimistic overrides,
- * context menu modal, song info modal, queue panel visibility (with
- * localStorage round-trip), fullscreen toggle, repeat mode cycle.
- *
- * Factored out of the playerStore `create()` body so the action set
- * stays a flat object literal instead of a giant inline block.
+ * Pure-UI state setters: no audio engine / network side effects.
+ * Add new actions here only if they fit that contract.
  */
 export function createUiStateActions(set: SetState): Pick<
   PlayerState,