refactor(lib): extract Track/QueueItemRef domain model to lib/media/trackTypes

Track is the app's normalized song model and QueueItemRef its thin queue
identity -- consumed app-wide (queue, cover, context menus, sharing, lucky-mix,
library browse), not a playback-internal detail. They lived in
features/playback/store/playerStoreTypes, forcing ~115 core/feature files to
reach into the playback feature for the central media type.

Move the two interfaces to lib/media/trackTypes; playerStoreTypes keeps
PlayerState and now imports them from lib. 115 importers repointed (mixed
'PlayerState, Track' lines split so PlayerState stays). Pure type move (erased at
runtime). tsc 0, lint 0.

src/features/playlist/components/PlaylistTracklist.tsx

@@ -11,7 +11,7 @@ import {
 } from 'lucide-react';
 import type { ColDef } from '@/utils/useTracklistColumns';
 import type { SubsonicSong } from '@/lib/api/subsonicTypes';
-import type { Track } from '@/features/playback/store/playerStoreTypes';
+import type { Track } from '@/lib/media/trackTypes';
 import { usePlayerStore } from '@/features/playback/store/playerStore';
 import { previewInputFromSong, usePreviewStore } from '@/features/playback/store/previewStore';
 import { useThemeStore } from '@/store/themeStore';

src/features/playlist/hooks/usePlaylistBulkPlayCallbacks.ts

@@ -1,5 +1,5 @@
 import { useCallback } from 'react';
-import type { Track } from '@/features/playback/store/playerStoreTypes';
+import type { Track } from '@/lib/media/trackTypes';
 import { enqueuePlaylistAll, playPlaylistAll, shufflePlaylistAll } from '@/features/playlist/utils/playlistBulkPlayActions';
 
 export interface PlaylistBulkPlayCallbacksDeps {

src/features/playlist/hooks/usePlaylistDerived.ts

@@ -1,6 +1,6 @@
 import { useMemo } from 'react';
 import type { SubsonicSong } from '@/lib/api/subsonicTypes';
-import type { Track } from '@/features/playback/store/playerStoreTypes';
+import type { Track } from '@/lib/media/trackTypes';
 import { usePlayerStore } from '@/features/playback/store/playerStore';
 import { songToTrack } from '@/features/playback/utils/playback/songToTrack';
 import { getDisplayedSongs, type PlaylistSortDir, type PlaylistSortKey } from '@/features/playlist/utils/playlistDisplayedSongs';

src/features/playlist/utils/playlistBulkPlayActions.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it, vi } from 'vitest';
 import { enqueuePlaylistAll, playPlaylistAll, shufflePlaylistAll } from '@/features/playlist/utils/playlistBulkPlayActions';
-import type { Track } from '@/features/playback/store/playerStoreTypes';
+import type { Track } from '@/lib/media/trackTypes';
 
 // Only id/queue identity matters for these actions.
 const tracks = [{ id: 'a' }, { id: 'b' }, { id: 'c' }] as unknown as Track[];

src/features/playlist/utils/playlistBulkPlayActions.ts

@@ -1,4 +1,4 @@
-import type { Track } from '@/features/playback/store/playerStoreTypes';
+import type { Track } from '@/lib/media/trackTypes';
 
 // No `touchPlaylist` here: playing/shuffling/enqueuing does not modify the
 // playlist. Touching it bumps `lastModified`, which is the playlist detail