fix(mpv): harden native initialization and logging

test/mpv/player_native_bridge_test.dart

@@ -1,3 +1,5 @@
+import 'dart:async' show Completer;
+
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:plezy/mpv/models.dart';
@@ -16,6 +18,41 @@ void main() {
     await SettingsService.getInstance();
   });
 
+  test('MPV coalesces concurrent Dart initialization requests', () async {
+    final initialize = Completer<bool>();
+    final calls = <MethodCall>[];
+
+    await withMockPlayerChannels(
+      methodChannelName: 'com.plezy/mpv_player',
+      eventChannelName: 'com.plezy/mpv_player/events',
+      methodHandler: (call) {
+        calls.add(call);
+        if (call.method == 'initialize') return initialize.future;
+        return Future.value(null);
+      },
+      testBody: () async {
+        final player = PlayerNative();
+        try {
+          final logLevel = player.setLogLevel('warn');
+          final command = player.command(['stop']);
+          await Future<void>.delayed(Duration.zero);
+
+          expect(calls.where((call) => call.method == 'initialize'), hasLength(1));
+
+          initialize.complete(true);
+          await Future.wait([logLevel, command]);
+
+          expect(calls.where((call) => call.method == 'initialize'), hasLength(1));
+          expect(calls.where((call) => call.method == 'setLogLevel'), hasLength(1));
+          expect(calls.where((call) => call.method == 'command'), hasLength(1));
+        } finally {
+          if (!initialize.isCompleted) initialize.complete(true);
+          await player.dispose();
+        }
+      },
+    );
+  });
+
   test('Android command failure reaches seek recovery', () async {
     await withMockPlayerChannels(
       methodChannelName: 'com.plezy/mpv_player',
@@ -64,6 +101,28 @@ void main() {
     );
   });
 
+  test('audio setLogLevel uses the dedicated native channel', () async {
+    MethodCall? logLevelCall;
+    await withMockPlayerChannels(
+      methodChannelName: 'com.plezy/mpv_audio_player',
+      eventChannelName: 'com.plezy/mpv_audio_player/events',
+      methodHandler: (call) async {
+        if (call.method == 'initialize') return true;
+        if (call.method == 'setLogLevel') logLevelCall = call;
+        return null;
+      },
+      testBody: () async {
+        final player = PlayerNative.audio();
+        try {
+          await player.setLogLevel('v');
+          expect(logLevelCall?.arguments, {'level': 'v'});
+        } finally {
+          await player.dispose();
+        }
+      },
+    );
+  });
+
   test('Android mpv end-file error preserves native diagnostic message', () async {
     await withMockPlayerChannels(
       methodChannelName: 'com.plezy/mpv_player',