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/components/business/ReportDialog/ReportDialog.tsx

@@ -4,7 +4,7 @@
  * 提供友好的用户界面和流畅的交互体验
  */
 
-import React, { useState, useCallback, useMemo } from 'react';
+import React, { useState, useCallback, useMemo, useEffect } from 'react';
 import {
   Modal,
   View,
@@ -62,6 +62,13 @@ const ReportDialog: React.FC<ReportDialogProps> = ({
 
   const targetConfig = TARGET_CONFIG[targetType];
 
+  useEffect(() => {
+    if (visible && Platform.OS === 'web') {
+      const active = (globalThis as any)?.document?.activeElement as { blur?: () => void } | undefined;
+      active?.blur?.();
+    }
+  }, [visible]);
+
   // 判断补充说明是否必填（选择"其他原因"时必填）
   const isDescriptionRequired = selectedReason === 'other';
   const descriptionPlaceholder = isDescriptionRequired