fix(app): Phase 1.1 紧急修复 — SyncEngine 接入 + authorId + catch 异常处理

- feat(sync): SyncEngine 接入 EditorPage, 保存时 enqueue + 网络恢复自动 trySync
- fix(editor): authorId 从 AuthBloc 获取, 替代硬编码 'local'
- fix(bloc): class_bloc/calendar/profile/parent catch(_).全部改为 debugPrint
- feat(editor): 编辑器工具栏拆分 (brush_panel/tag_panel/text_format_bar/dot_grid_painter)
- feat(editor): EditorBloc 扩展 + EditorPage 增强
- feat(search): SearchBloc 扩展搜索功能
- feat(home): HomeBloc/HomePage 增强
- feat(auth): LoginPage 增强
- feat(templates): TemplateGalleryPage 重构
- fix(web): 管理端班级/日记页面修复
- fix(server): comment_service + theme_handler 修复
- docs: 添加全链路审计报告和验证截图

app/lib/data/services/sync_engine.dart

@@ -12,10 +12,12 @@
 // - 联网后自动推送待同步操作
 // - 版本冲突时本地版本覆盖远端（简单策略）
 
+import 'dart:async';
 import 'dart:convert';
 import 'dart:collection';
 
 import 'package:connectivity_plus/connectivity_plus.dart';
+import 'package:flutter/foundation.dart';
 import 'package:isar/isar.dart';
 
 import '../local/isar_database.dart';
@@ -114,6 +116,7 @@ class PendingOperation {
 class SyncEngine {
   final ApiClient _apiClient;
   final Queue<PendingOperation> _pendingQueue = Queue();
+  StreamSubscription<List<ConnectivityResult>>? _connectivitySub;
 
   SyncStatus _status = SyncStatus.idle;
   String? _lastError;
@@ -289,6 +292,26 @@ class SyncEngine {
     }
   }
 
+  /// 启动网络监听 — 网络恢复时自动触发同步
+  ///
+  /// 在 app.dart 中创建 SyncEngine 后调用一次。
+  /// 调用 [dispose] 停止监听。
+  void startAutoSync() {
+    _connectivitySub = Connectivity().onConnectivityChanged.listen((result) {
+      final isOnline = result.any((r) => r != ConnectivityResult.none);
+      if (isOnline && _pendingQueue.isNotEmpty && _status != SyncStatus.syncing) {
+        debugPrint('SyncEngine: 网络恢复，开始同步 ${_pendingQueue.length} 个操作');
+        trySync();
+      }
+    });
+  }
+
+  /// 停止网络监听并清理资源
+  void dispose() {
+    _connectivitySub?.cancel();
+    _connectivitySub = null;
+  }
+
   // ============================================================
   // 转换函数
   // ============================================================