Player overlay v2: now/next with programme progress, audio track switching

- Overlay shows current programme (title, time range, EPG progress) and
  what's next; resurfaces briefly on programme change, hides after 5s.
- Audio tracks: listed from the stream, switchable via D-pad left/right
  on live streams (seek keeps left/right on seekable media), via chips
  in the overlay and from the phone remote (set_audio message).
- Main UI font switches to Inter; Space Grotesk stays for the wordmark.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app/src/main/java/dev/castarr/tv/AppState.kt

@@ -38,6 +38,9 @@ class AppState(
     var isLive by mutableStateOf(false)
     var favoritesOnly by mutableStateOf(false)
     var groupFilter by mutableStateOf<String?>(null)
+    var audioTracks by mutableStateOf<List<PlayerController.AudioTrack>>(emptyList())
+        private set
+    private var lastNowTitle: String? = null
 
     /** Phone-first onboarding progress (ADR-0007). */
     var welcomePhase by mutableStateOf(WelcomePhase.WAIT_PHONE)
@@ -158,13 +161,31 @@ class AppState(
     }
 
     fun syncFromPlayer() {
+        val previous = playerState
         playerState = player.state
+        if (playerState != previous) overlayVisible = true
         isLive = player.player.isCurrentMediaItemLive
         positionMs = player.player.currentPosition.coerceAtLeast(0)
         durationMs = player.player.duration.coerceAtLeast(0)
+        audioTracks = player.audioTracks()
+        // Briefly resurface the overlay when the running programme changes.
+        val nowTitle = currentChannel?.let { nowNext(it).now?.title }
+        if (playerVisible && nowTitle != null && lastNowTitle != null && nowTitle != lastNowTitle) {
+            overlayVisible = true
+        }
+        lastNowTitle = nowTitle
         if (!player.hasMedia && playerVisible) {
             playerVisible = false
             currentChannel = null
         }
     }
+
+    /** Steps to the next audio track (D-pad friendly: one key, cycles). */
+    fun cycleAudio(direction: Int) {
+        val tracks = audioTracks
+        if (tracks.size < 2) return
+        val current = tracks.indexOfFirst { it.selected }.coerceAtLeast(0)
+        player.selectAudio((current + direction + tracks.size) % tracks.size)
+        audioTracks = player.audioTracks()
+    }
 }