Slim PlayerViewModel: extract controller sync and playPause

[theovilardo]

Pass 8a - playPause + remote-queue reconciliation -> PlaybackDispatchStateHolder:

• Move playPause (cast pause/resume, remote-queue realignment, local controller resume/fallback paths) plus its hasRemoteQueueItems and remoteQueueMatchesLocalQueue helpers. Every dependency and callback it needs already existed in the dispatch holder.

Pass 8b - media-controller sync cluster -> new MediaControllerSyncStateHolder:

• Move the decomposed Player.Listener registrations (volume, playback state, media-item/timeline transitions incl. the EOT sleep timer and Telegram offline guard, tracks/metadata/shuffle/repeat), the initial controller-state snapshot, the queue snapshot rebuild with its timeline-signature dedupe, repeat-mode restore/flush, position sync, and the playback audio-metadata (format/bitrate/sample-rate) probing.
• The holder owns the listener registry, transition/buffering/probe jobs and the PlaybackAudioMetadata flow; the ViewModel re-exposes playbackAudioMetadata and supplies VM-owned state through one ControllerSyncCallbacks bundle set at init.
• ViewModel sheds the field-injected MediaMapper (now a holder ctor dep).
• PlayerViewModelTest constructs the real sync holder wired to the same mocks so the repeat-mode restore test keeps covering the moved logic.

All public ViewModel signatures preserved as thin delegates; no UI files change. PlayerViewModel: 3,962 -> 3,118 lines.

Verified: compileDebugKotlin, PlayerViewModelTest, PlayerViewModelHydrationTest, QueueStateHolderTest, PlaybackStateHolderTest.