fix(app): 18 处 catch(e) 添加 debugPrint 异常日志

- parent_bloc: 6 处 (LoadChildren/BindChild/ViewJournals/ExportData/DeleteData/UnbindChild)
- search_bloc: 3 处 (SearchByMood/SearchByTag/SearchByKeyword)
- achievement_bloc: 1 处 (_fetchAchievements)
- sticker_bloc: 2 处 (_fetchPacks/fetchStickersInPack)
- template_bloc: 1 处 (_fetchTemplates)
- mood_bloc: 1 处 (_loadStats)
- home_bloc: 1 处 (_onLoadData)
- calendar_bloc: 1 处 (_onMonthChanged)
- sync_engine: 1 处 (trySync)
- weekly_page: 已有 debugPrint，无需修改

app/lib/data/services/sync_engine.dart

@@ -196,6 +196,7 @@ class SyncEngine {
         _lastError = '同步中断：网络不可用';
         return;
       } catch (e) {
+        debugPrint('SyncEngine.trySync 操作失败: $e');
         // 操作失败，增加重试计数
         final retried = operation.copyWith(retryCount: operation.retryCount + 1);