refactor(message): replace SubscriptionManager with Zustand selectors

Remove custom SubscriptionManager class and adopt Zustand's built-in
selector mechanism for reactive state updates. This simplifies the
architecture by eliminating manual subscription management and relying
on Zustand's automatic dependency tracking for component re-renders.

Key changes:
- Remove SubscriptionManager class from store.ts
- Replace all notifySubscribers calls with direct store updates
- Update hooks to use Zustand selectors with useShallow for complex data
- Remove subscribe/unsubscribe patterns from MessageManager
- Simplify EmbeddedChat to use selector instead of local state
- Rename requestConversationListRefresh to refreshConversations

src/screens/message/ChatScreen.tsx

@@ -12,7 +12,7 @@
  * - useChatScreen.ts: 自定义Hook，管理所有状态和逻辑
  * - EmojiPanel.tsx: 表情面板组件
  * - MorePanel.tsx: 更多功能面板组件
- * - MentionPanel.tsx: @成员选择面板组件
+ * - MentionPanel.tsx: @成员选择  面板组件
  * - LongPressMenu.tsx: 长按菜单组件
  * - ChatHeader.tsx: 聊天头部组件
  * - MessageBubble.tsx: 消息气泡组件
@@ -258,10 +258,7 @@ export const ChatScreen: React.FC = () => {
   useEffect(() => {
     const unsubscribe = navigation.addListener('beforeRemove', () => {
       // 刷新会话列表，确保已读状态正确显示
-      messageManager.requestConversationListRefresh('chat-before-remove', {
-        force: true,
-        allowDefer: false,
-      });
+      messageManager.refreshConversations(true, 'chat-before-remove');
     });
     return unsubscribe;
   }, [navigation]);