fix(macos): reduce idle CPU when video player is paused

- Remove vulkan-swap-mode mailbox (continuous GPU rendering even when paused)
- End playback activity assertion on pause, restore on play
- Fix PerformanceStatsService persistent frame callback leak

lib/widgets/video_controls/widgets/performance_overlay/performance_stats_service.dart

@@ -33,6 +33,8 @@ class PerformanceStatsService {
   int _frameCount = 0;
   DateTime _lastFpsUpdate = DateTime.now();
   double? _currentUiFps;
+  bool _fpsTrackingActive = false;
+  bool _fpsCallbackRegistered = false;
 
   // Track runtime player type for logging (can differ from Dart object type after fallback)
   // Values: 'exoplayer', 'mpv', or 'unknown'
@@ -77,11 +79,16 @@ class PerformanceStatsService {
   void _startFpsTracking() {
     _frameCount = 0;
     _lastFpsUpdate = DateTime.now();
-    SchedulerBinding.instance.addPersistentFrameCallback(_onFrame);
+    _fpsTrackingActive = true;
+    if (!_fpsCallbackRegistered) {
+      _fpsCallbackRegistered = true;
+      SchedulerBinding.instance.addPersistentFrameCallback(_onFrame);
+    }
   }
 
   /// Called every frame to count FPS.
   void _onFrame(Duration timestamp) {
+    if (!_fpsTrackingActive) return;
     _frameCount++;
     final now = DateTime.now();
     final elapsed = now.difference(_lastFpsUpdate);
@@ -96,6 +103,8 @@ class PerformanceStatsService {
   void stopPolling() {
     _pollingTimer?.cancel();
     _pollingTimer = null;
+    _fpsTrackingActive = false;
+    _currentUiFps = null;
   }
 
   /// Fetch all performance stats from the player.

macos/Runner/MpvPlayer/MpvPlayerCore.swift

@@ -85,7 +85,7 @@ class MpvPlayerCore: MpvPlayerCoreBase {
     override func configurePlatformMpvOptions() {
         guard let mpv else { return }
         checkError(mpv_set_option_string(mpv, "ao", "avfoundation,coreaudio"))
-        checkError(mpv_set_option_string(mpv, "vulkan-swap-mode", "mailbox"))
+        // Default fifo (vsync) mode — mailbox was causing continuous GPU rendering even when paused
     }
 
     var videoLayer: CAMetalLayer? { metalLayer }
@@ -113,9 +113,13 @@ class MpvPlayerCore: MpvPlayerCoreBase {
         command(["seek", "0", "relative+exact"])
     }
 
+    private var isVisible = false
+
     func setVisible(_ visible: Bool) {
         guard let metalLayer, !isPipActive else { return }
 
+        isVisible = visible
+
         if visible {
             metalLayer.removeFromSuperlayer()
             if let superlayer = window?.contentView?.layer {
@@ -130,6 +134,14 @@ class MpvPlayerCore: MpvPlayerCoreBase {
         print("[MpvPlayerCore] setVisible(\(visible))")
     }
 
+    func setPaused(_ paused: Bool) {
+        if paused {
+            endPlaybackActivity()
+        } else if isVisible {
+            beginPlaybackActivity()
+        }
+    }
+
     func updateFrame(_ frame: CGRect? = nil) {
         guard let metalLayer, !isPipActive else { return }
 

macos/Runner/MpvPlayer/MpvPlayerPlugin.swift

@@ -277,6 +277,7 @@ class MpvPlayerPlugin: NSObject, FlutterPlugin, FlutterStreamHandler, MpvPluginS
         if name == "pause" {
             let isPlaying = value == "no"
             pipController?.setPlaying(isPlaying)
+            playerCore?.setPaused(!isPlaying)
         }
 
         result(nil)