refactor: migrate post operations to use case architecture with differential updates

Migrate post-related operations from direct service/store calls to a new use case architecture featuring differential updates. Key changes include: (1) introduce ProcessPostUseCase to handle like, unlike, favorite, unfavorite, delete, and fetch operations with proper state management, (2) add useDifferentialPosts hook for efficient list rendering with minimal re-renders, (3) add PostDiffCalculator and PostUpdateBatcher in infrastructure layer for incremental updates, (4) deprecate NotificationItem component in favor of SystemMessageItem, (5) remove deprecated interactive methods from userStore, (6) add posts_cache table to local datasource, (7) clean up legacy MessageDTO and ConversationDTO types, (8) remove deprecated hook useBreakpointCheck, (9) refactor MessageBubble to use measureInWindow directly for better React Native compatibility

src/screens/message/NotificationsScreen.tsx

@@ -29,7 +29,8 @@ import { SystemMessageItem } from '../../components/business';
 import { Text, EmptyState, ResponsiveContainer } from '../../components/common';
 import { useCursorPagination } from '../../hooks/useCursorPagination';
 import { RootStackParamList } from '../../navigation/types';
-import { useMessageManagerSystemUnreadCount, useUserStore } from '../../stores';
+import { useMessageManagerSystemUnreadCount } from '../../stores';
+import { messageManager } from '../../stores/messageManager';
 
 const MESSAGE_TYPES = [
   { key: 'all', title: '全部' },
@@ -46,7 +47,6 @@ const GROUP_SYSTEM_TYPES = new Set(['group_invite', 'group_join_apply', 'group_j
 
 export const NotificationsScreen: React.FC<{ onBack?: () => void }> = ({ onBack }) => {
   const isFocused = useIsFocused();
-  const fetchMessageUnreadCount = useUserStore(state => state.fetchMessageUnreadCount);
   const { setSystemUnreadCount, decrementSystemUnreadCount } = useMessageManagerSystemUnreadCount();
   const navigation = useNavigation<NativeStackNavigationProp<RootStackParamList>>();
 
@@ -158,11 +158,11 @@ export const NotificationsScreen: React.FC<{ onBack?: () => void }> = ({ onBack
       setUnreadCount(0);
       setSystemUnreadCount(0);
       // 同步更新全局 TabBar 红点
-      fetchMessageUnreadCount();
+      messageManager.fetchUnreadCount();
     } catch (error) {
       console.error('一键已读失败:', error);
     }
-  }, [refresh, fetchMessageUnreadCount, setSystemUnreadCount]);
+  }, [refresh, setSystemUnreadCount]);
 
   // 页面加载和获得焦点时刷新，并自动标记所有消息为已读
   // 使用 ref 防止重复执行，避免无限循环
@@ -281,7 +281,7 @@ export const NotificationsScreen: React.FC<{ onBack?: () => void }> = ({ onBack
       }
       // 更新本地未读数以及全局 TabBar 红点
       fetchUnreadCount();
-      fetchMessageUnreadCount();
+      messageManager.fetchUnreadCount();
 
       // 根据消息类型处理导航
       const { system_type, extra_data } = message;