fix(player): 分离首页与播放页播放上下文

test/playback/playback_session_test.dart

@@ -32,6 +32,33 @@ void main() {
     await session.close();
   });
 
+  test('should_keep_only_current_player_when_neighbor_warmup_disabled', () async {
+    final factory = FakeFactory();
+    final session = PlaybackSession(
+      episodes: episodes,
+      factory: factory.create,
+      canPlay: (episode) => episode.isFree,
+      warmNeighborsEnabled: false,
+    );
+
+    await session.select(0, preloadIndex: 1);
+    await session.preloadSettled;
+    expect(factory.created, hasLength(1));
+    expect(factory.live, 1);
+    expect(session.preloadedIndex, isNull);
+
+    final first = factory.created.single;
+    await session.select(1, preloadIndex: 2, previousIndex: 0);
+    await session.preloadSettled;
+
+    expect(first.disposed, isTrue);
+    expect(factory.created, hasLength(2));
+    expect(factory.live, 1);
+    expect(session.livePlayerCount, 1);
+    expect(session.active, same(factory.created.last));
+    await session.close();
+  });
+
   test('should_release_previous_player_immediately_when_selecting_locked', () async {
     final lockedEpisodes = [
       Episode(