refactor: remove AudioService from ContentView — all playback state via PlayerViewModel

Music/ContentView.swift

@@ -5,7 +5,6 @@ struct ContentView: View {
     var library: LibraryViewModel
     var player: PlayerViewModel
     var scanner: ScannerService
-    var audio: AudioService
     var playlist: PlaylistViewModel
     var shazam: ShazamService
     var db: DatabaseService
@@ -204,9 +203,6 @@ struct ContentView: View {
             handleDrop(providers)
             return true
         }
-        .onChange(of: audio.currentTime) { _, _ in
-            player.checkHalfway()
-        }
         .onChange(of: library.trackCount) { _, _ in
             if showHome { loadHomeData() }
         }
@@ -289,10 +285,10 @@ struct ContentView: View {
     private var playerControls: some View {
         PlayerControlsView(
             currentTrack: player.currentTrack,
-            isPlaying: audio.isPlaying,
-            currentTime: audio.currentTime,
-            duration: audio.duration,
-            volume: audio.volume,
+            isPlaying: player.isPlaying,
+            currentTime: player.currentTime,
+            duration: player.duration,
+            volume: player.volume,
             isShuffled: player.isShuffled,
             onPlayPause: {
                 if player.currentTrack == nil {
@@ -302,23 +298,23 @@ struct ContentView: View {
                         player.play(first)
                     }
                 } else {
-                    audio.togglePlayPause()
+                    player.togglePlayPause()
                 }
             },
             onNext: { player.next() },
             onPrevious: { player.previous() },
-            onSeek: { audio.seek(to: $0) },
-            onScrubStart: { audio.beginScrubbing() },
-            onScrub: { audio.scrub(to: $0) },
-            onScrubEnd: { audio.endScrubbing(at: $0) },
-            onVolumeChange: { audio.volume = $0 },
+            onSeek: { player.seek(to: $0) },
+            onScrubStart: { player.beginScrubbing() },
+            onScrub: { player.scrub(to: $0) },
+            onScrubEnd: { player.endScrubbing(at: $0) },
+            onVolumeChange: { player.setVolume($0) },
             onShuffleToggle: { player.toggleShuffle() },
             onNowPlayingTap: { scrollToPlayingTrigger = UUID() }
         )
     }
 
     private func installKeyboardMonitor() {
-        keyMonitor = NSEvent.addLocalMonitorForEvents(matching: .keyDown) { [audio, player, library, playlist] event in
+        keyMonitor = NSEvent.addLocalMonitorForEvents(matching: .keyDown) { [player, library, playlist] event in
             guard event.modifierFlags.intersection([.command, .control, .option, .shift]).isEmpty else {
                 return event
             }
@@ -335,7 +331,7 @@ struct ContentView: View {
                         player.play(first)
                     }
                 } else {
-                    audio.togglePlayPause()
+                    player.togglePlayPause()
                 }
                 return nil
             case 123: // left arrow

Music/MusicApp.swift

@@ -24,7 +24,6 @@ struct MusicApp: App {
                         library: library,
                         player: player,
                         scanner: scanner,
-                        audio: audioService,
                         playlist: playlist,
                         shazam: shazamService,
                         db: db,