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

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)