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/features/mood/bloc/mood_bloc.dart

@@ -138,6 +138,7 @@ class MoodBloc extends ChangeNotifier {
         ),
       );
     } catch (e) {
+      debugPrint('MoodBloc._loadStats 失败: $e');
       _state = _state.copyWith(
         isLoading: false,
         errorMessage: '加载统计数据失败',