feat(app): 完善播放协议搜索与空状态

test/player/player_more_sheet_test.dart

@@ -118,6 +118,75 @@ void main() {
     expect(disabledText.style?.color, AppColors.subtle);
   });
 
+  testWidgets('should_enable_quality_when_ticket_uses_lowercase_codes', (
+    tester,
+  ) async {
+    await _openSheet(
+      tester,
+      qualities: const ['AUTO', '360p', '480p', '720p', '1080p'],
+    );
+
+    expect(find.text('720P'), findsOneWidget);
+    expect(find.text('1080P'), findsOneWidget);
+    expect(find.textContaining('暂不可用'), findsNothing);
+    final enabled = tester.widget<Text>(
+      find.descendant(
+        of: find.byKey(const Key('player-more-quality-720P')),
+        matching: find.byType(Text),
+      ),
+    );
+    expect(enabled.style?.color, isNot(AppColors.subtle));
+  });
+
+  testWidgets('should_report_selected_quality_when_a_rendition_is_tapped', (
+    tester,
+  ) async {
+    String? picked;
+    await _openSheet(
+      tester,
+      qualities: const ['AUTO', '720p'],
+      onQuality: (quality) async {
+        picked = quality;
+        return true;
+      },
+    );
+
+    await tester.ensureVisible(find.byKey(const Key('player-more-quality-720P')));
+    await tester.tap(find.byKey(const Key('player-more-quality-720P')));
+    await tester.pump();
+
+    expect(picked, '720P');
+    final selected = tester.widget<Text>(
+      find.descendant(
+        of: find.byKey(const Key('player-more-quality-720P')),
+        matching: find.byType(Text),
+      ),
+    );
+    expect(selected.style?.color, AppColors.onSurface);
+  });
+
+  testWidgets('should_restore_previous_quality_when_switch_fails', (
+    tester,
+  ) async {
+    await _openSheet(
+      tester,
+      qualities: const ['AUTO', '720p'],
+      onQuality: (_) async => false,
+    );
+
+    await tester.ensureVisible(find.byKey(const Key('player-more-quality-720P')));
+    await tester.tap(find.byKey(const Key('player-more-quality-720P')));
+    await tester.pumpAndSettle();
+
+    final restored = tester.widget<Text>(
+      find.descendant(
+        of: find.byKey(const Key('player-more-quality-AUTO')),
+        matching: find.byType(Text),
+      ),
+    );
+    expect(restored.style?.color, AppColors.onSurface);
+  });
+
   testWidgets('should_trigger_pip_and_close_sheet_when_tapped', (tester) async {
     var pipCalls = 0;
     await _openSheet(tester, onPip: () => pipCalls++);
@@ -142,7 +211,12 @@ void main() {
   });
 }
 
-Future<void> _openSheet(WidgetTester tester, {VoidCallback? onPip}) async {
+Future<void> _openSheet(
+  WidgetTester tester, {
+  VoidCallback? onPip,
+  Future<bool> Function(String quality)? onQuality,
+  List<String> qualities = const ['AUTO'],
+}) async {
   await tester.pumpWidget(
     MaterialApp(
       supportedLocales: AppLocalizations.supportedLocales,
@@ -158,11 +232,12 @@ Future<void> _openSheet(WidgetTester tester, {VoidCallback? onPip}) async {
                 isScrollControlled: true,
                 builder: (_) => PlayerMoreSheet(
                   l10n: AppLocalizations.of(context)!,
-                  state: const PlayerMoreState(speed: 1.0, qualities: ['AUTO']),
+                  state: PlayerMoreState(speed: 1.0, qualities: qualities),
                   actions: PlayerMoreActions(
                     onSpeedChanged: (_) {},
                     onClear: () {},
                     onDownload: () {},
+                    onQualityChanged: onQuality ?? (_) async => true,
                     onPip: onPip,
                   ),
                 ),