feat(flutter): 重构播放页并增加语言切换

test/core/locale_controller_test.dart

@@ -0,0 +1,39 @@
+// Author: fruit.com.cn
+
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:fruitshorts/core/data/services/locale_controller.dart';
+import 'package:shared_preferences_platform_interface/in_memory_shared_preferences_async.dart';
+import 'package:shared_preferences_platform_interface/shared_preferences_async_platform_interface.dart';
+
+void main() {
+  setUp(() {
+    SharedPreferencesAsyncPlatform.instance =
+        InMemorySharedPreferencesAsync.empty();
+  });
+
+  test('should_restore_saved_locale_when_controller_loads', () async {
+    SharedPreferencesAsyncPlatform.instance =
+        InMemorySharedPreferencesAsync.withData({
+          LocaleController.preferenceKey: 'zh',
+        });
+    final controller = LocaleController();
+
+    await controller.load();
+
+    expect(controller.locale?.languageCode, 'zh');
+    controller.dispose();
+  });
+
+  test('should_persist_selected_locale_for_next_launch', () async {
+    final controller = LocaleController();
+    await controller.select(const Locale('id'));
+
+    final restored = LocaleController();
+    await restored.load();
+
+    expect(restored.locale?.languageCode, 'id');
+    controller.dispose();
+    restored.dispose();
+  });
+}