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/stores/chatSettingsStore.ts

@@ -81,6 +81,132 @@ export const CHAT_THEMES = [
     textPrimary: '#1A1A1A',
     textSecondary: '#666666',
   },
+  { 
+    id: 'coral', 
+    name: '珊瑚橙', 
+    primary: '#FF6B6B', 
+    secondary: '#FFF0F0', 
+    bubble: '#FFD4D4', 
+    icon: '🐠',
+    card: '#FFFFFF',
+    inputBg: '#FFFFFF',
+    panelBg: '#FFF5F5',
+    headerBg: '#FFFFFF',
+    textPrimary: '#1A1A1A',
+    textSecondary: '#666666',
+  },
+  { 
+    id: 'rose', 
+    name: '玫瑰粉', 
+    primary: '#E91E63', 
+    secondary: '#FCE4EC', 
+    bubble: '#F8BBD9', 
+    icon: '🌹',
+    card: '#FFFFFF',
+    inputBg: '#FFFFFF',
+    panelBg: '#FCE4EC',
+    headerBg: '#FFFFFF',
+    textPrimary: '#1A1A1A',
+    textSecondary: '#666666',
+  },
+  { 
+    id: 'indigo', 
+    name: '靛蓝紫', 
+    primary: '#3F51B5', 
+    secondary: '#E8EAF6', 
+    bubble: '#C5CAE9', 
+    icon: '🐉',
+    card: '#FFFFFF',
+    inputBg: '#FFFFFF',
+    panelBg: '#E8EAF6',
+    headerBg: '#FFFFFF',
+    textPrimary: '#1A1A1A',
+    textSecondary: '#666666',
+  },
+  { 
+    id: 'mint', 
+    name: '薄荷绿', 
+    primary: '#00BCD4', 
+    secondary: '#E0F7FA', 
+    bubble: '#B2EBF2', 
+    icon: '🧊',
+    card: '#FFFFFF',
+    inputBg: '#FFFFFF',
+    panelBg: '#E0F7FA',
+    headerBg: '#FFFFFF',
+    textPrimary: '#1A1A1A',
+    textSecondary: '#666666',
+  },
+  { 
+    id: 'cherry', 
+    name: '樱桃红', 
+    primary: '#D32F2F', 
+    secondary: '#FFEBEE', 
+    bubble: '#FFCDD2', 
+    icon: '🍒',
+    card: '#FFFFFF',
+    inputBg: '#FFFFFF',
+    panelBg: '#FFEBEE',
+    headerBg: '#FFFFFF',
+    textPrimary: '#1A1A1A',
+    textSecondary: '#666666',
+  },
+  { 
+    id: 'lavender', 
+    name: '薰衣草', 
+    primary: '#7E57C2', 
+    secondary: '#EDE7F6', 
+    bubble: '#D1C4E9', 
+    icon: '💜',
+    card: '#FFFFFF',
+    inputBg: '#FFFFFF',
+    panelBg: '#EDE7F6',
+    headerBg: '#FFFFFF',
+    textPrimary: '#1A1A1A',
+    textSecondary: '#666666',
+  },
+  { 
+    id: 'sunset', 
+    name: '落日橙', 
+    primary: '#FF5722', 
+    secondary: '#FBE9E7', 
+    bubble: '#FFCCBC', 
+    icon: '🌅',
+    card: '#FFFFFF',
+    inputBg: '#FFFFFF',
+    panelBg: '#FBE9E7',
+    headerBg: '#FFFFFF',
+    textPrimary: '#1A1A1A',
+    textSecondary: '#666666',
+  },
+  { 
+    id: 'ocean', 
+    name: '深海蓝', 
+    primary: '#006064', 
+    secondary: '#B2EBF2', 
+    bubble: '#80DEEA', 
+    icon: '🌊',
+    card: '#FFFFFF',
+    inputBg: '#FFFFFF',
+    panelBg: '#E0F7FA',
+    headerBg: '#FFFFFF',
+    textPrimary: '#1A1A1A',
+    textSecondary: '#666666',
+  },
+  { 
+    id: 'forest', 
+    name: '森林绿', 
+    primary: '#1B5E20', 
+    secondary: '#C8E6C9', 
+    bubble: '#A5D6A7', 
+    icon: '🌳',
+    card: '#FFFFFF',
+    inputBg: '#FFFFFF',
+    panelBg: '#E8F5E9',
+    headerBg: '#FFFFFF',
+    textPrimary: '#1A1A1A',
+    textSecondary: '#666666',
+  },
 ] as const;
 
 export type ChatThemeId = typeof CHAT_THEMES[number]['id'];