fix(player): 预热直出并与视频统一封面布局

test/playback/playback_preload_test.dart

@@ -161,11 +161,13 @@ void main() {
     await session.select(2, preloadIndex: 3, previousIndex: 1);
     await session.preloadSettled;
     expect(session.active, isA<_Player>().having((p) => p.id, 'id', 'ep-2'));
+    expect(session.reusedWarmAt(2), isTrue);
 
     await session.select(1, preloadIndex: 2, previousIndex: 0);
     await session.preloadSettled;
 
     expect(session.active, isA<_Player>().having((p) => p.id, 'id', 'ep-1'));
+    expect(session.reusedWarmAt(1), isTrue);
     expect(
       factory.players.firstWhere((player) => player.id == 'ep-1').playing,
       isTrue,