fix(player): 优化封面过渡与换集起播

test/playback/playback_preload_test.dart

@@ -174,7 +174,7 @@ void main() {
     await session.close();
   });
 
-  test('should_keep_manual_pause_when_returning_to_same_episode', () async {
+  test('should_auto_play_previous_after_switching_from_paused_episode', () async {
     final factory = _Factory();
     final session = PlaybackSession(
       episodes: episodes,
@@ -195,13 +195,16 @@ void main() {
       factory.players.firstWhere((player) => player.id == 'ep-2').playing,
       isTrue,
     );
+    session.setUserWantsPlay(false);
+    await session.playbackSettled;
+    expect(session.userWantsPlay, isFalse);
 
     await session.select(1, preloadIndex: 2, previousIndex: 0);
     await session.preloadSettled;
-    expect(session.userWantsPlay, isFalse);
+    expect(session.userWantsPlay, isTrue);
     expect(
       factory.players.firstWhere((player) => player.id == 'ep-1').playing,
-      isFalse,
+      isTrue,
     );
     await session.close();
   });