Fixed small bug in cached play offset

app/src/main/java/com/keylightpiano/pianotimeline/ui/RecordingListViewModel.kt

@@ -272,11 +272,15 @@ class RecordingListViewModel(app: Application) : AndroidViewModel(app) {
         }
 
         // Throttled persistence of the current track + offset: at most once per
-        // second, and only while a track is loaded. Saving live (every 200ms
-        // position tick) would hammer DataStore; 1s is plenty for resume.
+        // second, and only while a track is actively PLAYING. Saving while paused
+        // is both unnecessary (a paused position doesn't change) and harmful: on
+        // restore, preparePaused seeks asynchronously, so ExoPlayer briefly reports
+        // position 0 before the seek lands — saving during that window would clobber
+        // the good offset with 0. Gating on isPlaying closes that window.
         viewModelScope.launch {
             var lastSaveAt = 0L
             playbackState.collect { s ->
+                if (!s.isPlaying) return@collect
                 val id = s.nowPlayingId ?: return@collect
                 val now = System.currentTimeMillis()
                 if (now - lastSaveAt >= 1000L) {