feat(app): 播放器增加清晰度档位入口

lib/core/data/models/play_ticket.dart

@@ -13,6 +13,7 @@ class PlayTicket {
     this.durationSec = 0,
     this.unlockCoin = 0,
     this.previewSeconds = 0,
+    this.qualities = const [],
   });
 
   static const String free = 'FREE';
@@ -35,6 +36,9 @@ class PlayTicket {
   /// 试看秒数：仅 `COIN_REQUIRED` 时有意义（付费解锁在 B2 做）。
   final int previewSeconds;
 
+  /// 后端下发的清晰度档位（如 AUTO / 720P / 1080P），HLS 由播放器自动切换。
+  final List<String> qualities;
+
   bool get needsUnlock =>
       accessType == coinRequired || accessType == vipRequired;
 
@@ -50,6 +54,10 @@ class PlayTicket {
       durationSec: jsonToInt(json['durationSec']),
       unlockCoin: jsonToInt(json['unlockCoin']),
       previewSeconds: jsonToInt(json['previewSeconds']),
+      qualities: (json['qualities'] as List? ?? const [])
+          .whereType<String>()
+          .where((quality) => quality.isNotEmpty)
+          .toList(),
     );
   }
 }

lib/core/data/repositories/playback_repository.dart

@@ -91,6 +91,7 @@ class FakePlaybackRepository implements PlaybackRepository {
           accessible: true,
           accessType: PlayTicket.free,
           playUrl: '/files/episode/fake-$episodeId.mp4?e=1&s=abc',
+          qualities: const ['AUTO', '720P', '1080P'],
         );
   }
 }