refactor(database): migrate to new modular database layer and unify data access

- Remove legacy database.ts, LocalDataSource.ts, and MessageRepository.ts
- Create new src/database/ module with messageRepository, userCacheRepository, conversationRepository, and groupCacheRepository
- Update all consumers to import from @/database instead of services/database
- Add web platform blur handling for modal components to fix focus issues
- Flatten SystemMessageItem and NotificationsScreen styles for consistent design
- Add draggable slider in ChatSettingsScreen and dynamic font size support
- Introduce 9 new chat color themes
- Add profile screens for about, terms, and privacy policy with navigation routes
- Add policy links to login and registration screens
- Fix post share URL format from /posts/ to /post/

src/screens/schedule/ScheduleScreen.tsx

@@ -16,6 +16,7 @@ import {
   TextInput,
   Alert,
   ActivityIndicator,
+  Platform,
 } from 'react-native';
 import { PanGestureHandler, State } from 'react-native-gesture-handler';
 import type { PanGestureHandlerStateChangeEvent } from 'react-native-gesture-handler';
@@ -212,6 +213,13 @@ export const ScheduleScreen: React.FC = () => {
   const [syncPassword, setSyncPassword] = useState('');
   const [isSyncing, setIsSyncing] = useState(false);
 
+  useEffect(() => {
+    if ((isAddModalVisible || isSettingsModalVisible || isSyncModalVisible) && Platform.OS === 'web') {
+      const active = (globalThis as any)?.document?.activeElement as { blur?: () => void } | undefined;
+      active?.blur?.();
+    }
+  }, [isAddModalVisible, isSettingsModalVisible, isSyncModalVisible]);
+
   // 组件卸载时设置标记
   useEffect(() => {
     return () => {