fix(player): 使用高清首帧并稳定切集占位

test/player/player_logic_test.dart

@@ -393,6 +393,35 @@ void main() {
     expect(logic.sessionEpisodes.first.videoUrl, 'file:///local/signal-1.mp4');
   });
 
+  test('should_write_ticket_poster_url_into_session_episode', () async {
+    final logic = _logic(
+      FakeWatchHistory(),
+      playback: FakePlaybackRepository(
+        ticket: const PlayTicket(
+          episodeId: 'signal-1',
+          accessible: true,
+          accessType: PlayTicket.free,
+          playUrl: '/files/signal-1.mp4',
+          posterUrl: '/files/transcoded/signal-1/poster.jpg',
+        ),
+      ),
+    );
+    logic.attach(
+      PlayerPage(drama: _drama('signal'), initialIndex: 0),
+      isMounted: () => true,
+    );
+    logic.start(factory: _RecordingFactory().create, coordinator: PlaybackCoordinator());
+    await _drain(logic);
+
+    expect(
+      logic.sessionEpisodes.first.posterUrl,
+      '/files/transcoded/signal-1/poster.jpg',
+    );
+
+    logic.dispose();
+    await _drain(logic);
+  });
+
   group('surface flags', () {
     test('should_set_immersive_when_picture_in_picture_callback_fires', () async {
       final factory = _RecordingFactory();