fix(mac): Fix NaN crash in slider and synchronize native player disposal

Guard slider position calculation against division by zero to prevent NaN crashes in Material3 Slider semantics. Make native player disposal synchronous (matching Linux behavior) to ensure cleanup completes before ioScope cancellation, preventing audio leaks. Use runBlocking(frameDispatcher) to safely close bitmaps on the same dispatcher that rendering uses, avoiding use-after-free race conditions.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: kdroidFilter

mediaplayer/src/jvmMain/kotlin/io/github/kdroidfilter/composemediaplayer/mac/MacVideoPlayerState.kt

@@ -666,7 +666,7 @@ class MacVideoPlayerState : VideoPlayerState {
                 }
             } else {
                 // Update slider position, batched with other UI updates to reduce main thread calls
-                val newSliderPos = (current / duration * 1000).toFloat().coerceIn(0f, 1000f)
+                val newSliderPos = if (duration > 0) (current / duration * 1000).toFloat().coerceIn(0f, 1000f) else 0f
                 withContext(Dispatchers.Main) {
                     sliderPos = newSliderPos
                 }
@@ -861,38 +861,33 @@ class MacVideoPlayerState : VideoPlayerState {
         uiUpdateJob?.cancel()
         playerScope.cancel()
 
-        ioScope.launch {
-            // Get player pointer and clear cached bitmaps while frame updates are paused.
-            val ptrToDispose =
-                withContext(frameDispatcher) {
-                    val ptrToDispose = playerPtrAtomic.getAndSet(0L)
-
-                    skiaBitmapA?.close()
-                    skiaBitmapB?.close()
-                    skiaBitmapA = null
-                    skiaBitmapB = null
-                    skiaBitmapWidth = 0
-                    skiaBitmapHeight = 0
-                    nextSkiaBitmapA = true
-
-                    ptrToDispose
-                }
+        // Dispose synchronously to guarantee cleanup before ioScope is cancelled —
+        // otherwise AVPlayer keeps running (audio leak).
+        // Use frameDispatcher to safely close bitmaps (rendering accesses them there).
+        val ptrToDispose = runBlocking(frameDispatcher) {
+            val ptr = playerPtrAtomic.getAndSet(0L)
+
+            skiaBitmapA?.close()
+            skiaBitmapB?.close()
+            skiaBitmapA = null
+            skiaBitmapB = null
+            skiaBitmapWidth = 0
+            skiaBitmapHeight = 0
+            nextSkiaBitmapA = true
+
+            ptr
+        }
 
-            // Dispose native resources outside the mutex lock
-            if (ptrToDispose != 0L) {
-                macLogger.d { "dispose() - Disposing native player" }
-                try {
-                    MacNativeBridge.nDisposePlayer(ptrToDispose)
-                } catch (e: Exception) {
-                    if (e is CancellationException) throw e
-                    macLogger.e { "Error disposing player: ${e.message}" }
-                }
+        if (ptrToDispose != 0L) {
+            macLogger.d { "dispose() - Disposing native player" }
+            try {
+                MacNativeBridge.nDisposePlayer(ptrToDispose)
+            } catch (e: Exception) {
+                if (e is CancellationException) throw e
+                macLogger.e { "Error disposing player: ${e.message}" }
             }
-
-            resetState()
         }
 
-        // Cancel ioScope last to ensure cleanup completes
         ioScope.cancel()
     }