feat(app): 剧场列表增加语种筛选

lib/pages/discover/discover_logic.dart

@@ -36,6 +36,7 @@ class DiscoverLogic extends ChangeNotifier {
   Duration searchDebounce = const Duration(milliseconds: 350);
   static const int searchPageSize = 20;
   List<Drama> searchResults = const [];
+  String? selectedLanguage;
   int searchTotal = 0;
   bool searchLoading = false;
   String? searchError;
@@ -87,8 +88,32 @@ class DiscoverLogic extends ChangeNotifier {
 
   /// 搜索态展示后端结果，非搜索态展示剧场自身的可见短剧。
   List<Drama> visibleDramas(List<Drama> fallback) {
-    if (!hasSearchQuery) return fallback;
-    return searchResults;
+    if (!hasSearchQuery) return _filterByLanguage(fallback);
+    return _filterByLanguage(searchResults);
+  }
+
+  /// 当前 feed 中出现过的语种，按首次出现顺序去重。
+  List<String> languagesOf(List<Drama> dramas) {
+    final languages = <String>[];
+    for (final drama in dramas) {
+      final language = drama.language;
+      if (language.isNotEmpty && !languages.contains(language)) {
+        languages.add(language);
+      }
+    }
+    return languages;
+  }
+
+  /// 按语种筛选；null 表示全部。
+  void selectLanguage(String? code) {
+    selectedLanguage = code;
+    notify();
+  }
+
+  List<Drama> _filterByLanguage(List<Drama> dramas) {
+    final code = selectedLanguage;
+    if (code == null) return dramas;
+    return dramas.where((drama) => drama.language == code).toList();
   }
 
   Future<void> retrySearch() async {

lib/pages/discover/discover_view.dart

@@ -176,7 +176,12 @@ class _DiscoverPageState extends State<DiscoverPage> {
             child: _categories(l10n, categories),
           ),
         ),
-        if (logic.resumeRecord != null && logic.resumeDrama(allDramas) != null)
+        SliverToBoxAdapter(
+          child: Padding(
+            padding: const EdgeInsets.fromLTRB(0, 0, 0, 12),
+            child: _languages(l10n, allDramas),
+          ),
+        ),        if (logic.resumeRecord != null && logic.resumeDrama(allDramas) != null)
           SliverToBoxAdapter(
             child: Padding(
               padding: const EdgeInsets.fromLTRB(16, 0, 16, 14),
@@ -427,6 +432,69 @@ class _DiscoverPageState extends State<DiscoverPage> {
     );
   }
 
+  Widget _languages(AppLocalizations l10n, List<Drama> dramas) {
+    final languages = logic.languagesOf(dramas);
+    if (languages.isEmpty) return const SizedBox.shrink();
+    final selected = logic.selectedLanguage;
+    return SizedBox(
+      key: const Key('discover-language-chips'),
+      height: AppDimens.tapTarget,
+      child: ListView(
+        padding: const EdgeInsets.symmetric(horizontal: 14),
+        scrollDirection: Axis.horizontal,
+        children: [
+          _languageChip(
+            key: const Key('discover-language-all'),
+            label: l10n.all,
+            selected: selected == null,
+            onTap: () => logic.selectLanguage(null),
+          ),
+          for (final language in languages)
+            _languageChip(
+              key: Key('discover-language-$language'),
+              label: _languageLabel(l10n, language),
+              selected: selected == language,
+              onTap: () => logic.selectLanguage(language),
+            ),
+        ],
+      ),
+    );
+  }
+
+  Widget _languageChip({
+    required Key key,
+    required String label,
+    required bool selected,
+    required VoidCallback onTap,
+  }) {
+    return Padding(
+      padding: const EdgeInsets.only(right: 8),
+      child: Center(
+        child: ChoiceChip(
+          key: key,
+          label: Text(label),
+          selected: selected,
+          showCheckmark: false,
+          onSelected: (_) => onTap(),
+          selectedColor: AppColors.blue,
+          backgroundColor: const Color(0xFF29272B),
+          side: BorderSide.none,
+          labelStyle: TextStyle(
+            color: selected ? AppColors.onPrimary : AppColors.muted,
+            fontSize: AppDimens.chipFont,
+            fontWeight: selected ? FontWeight.w700 : FontWeight.w500,
+          ),
+        ),
+      ),
+    );
+  }
+
+  String _languageLabel(AppLocalizations l10n, String code) {
+    if (code == 'zh-CN' || code == 'zh') return l10n.languageChinese;
+    if (code == 'id') return l10n.languageIndonesian;
+    if (code == 'en') return l10n.languageEnglish;
+    return code;
+  }
   Widget _continueCard(
     AppLocalizations l10n,
     Drama drama,