feat: 完善芽说英语品牌Logo与图标配置，完成跨平台云端同步服务开发与自动化部署

kouyu_english/lib/core/app_state.dart

@@ -13,6 +13,7 @@ import 'seed_courses.dart';
 import 'ai_config.dart';
 import 'ai_service.dart';
 import 'sherpa_stt_service.dart';
+import 'sync/sync_coordinator.dart';
 
 class AppState extends ChangeNotifier {
   static const _storageKey = 'learning_state_v1';
@@ -591,6 +592,7 @@ class AppState extends ChangeNotifier {
               (turn) => DialogueTurn(
                 text: turn['text'] as String,
                 isLearner: turn['isLearner'] as bool? ?? false,
+                translation: turn['translation'] as String?,
               ),
             )
             .toList(),
@@ -763,6 +765,7 @@ class AppState extends ChangeNotifier {
                       (turn) => {
                         'text': turn.text,
                         'isLearner': turn.isLearner,
+                        'translation': turn.translation,
                       },
                     )
                     .toList(),
@@ -815,6 +818,7 @@ class AppState extends ChangeNotifier {
   void finishOnboarding() {
     onboardingComplete = true;
     notifyListeners();
+    SyncCoordinator.instance.triggerBackgroundSync(this);
   }
 
   void setGoal(LearningGoal value) {
@@ -978,6 +982,7 @@ class AppState extends ChangeNotifier {
     }
     _resetLessonFlow();
     notifyListeners();
+    SyncCoordinator.instance.triggerBackgroundSync(this);
   }
 
   void _resetLessonFlow() {
@@ -1006,6 +1011,7 @@ class AppState extends ChangeNotifier {
     completeSegment(activeLessonId, index);
     _resetLessonFlow();
     notifyListeners();
+    SyncCoordinator.instance.triggerBackgroundSync(this);
   }
 
   void completeReview(
@@ -1066,6 +1072,7 @@ class AppState extends ChangeNotifier {
       rawAnswer: rawAnswer,
     );
     notifyListeners();
+    SyncCoordinator.instance.triggerBackgroundSync(this);
   }
 
   void reportReviewFailure(ReviewItem item) {