feat(message): enhance message store management and UI stability

Implement `removeMessage` in `useMessageStore` to allow for atomic message deletion from the state. Improve `useChatScreen` loading logic to prevent layout jumps and ensure consistent UI state during initial message loading. Additionally, add type safety for WebSocket sequence numbers and optimize message selector stability.

- Add `removeMessage` action to `useMessageStore` for state-consistent deletions
- Refine `useChatScreen` loading state logic to prevent FlashList layout issues
- Ensure `useMessages` hook returns a stable `EMPTY_MESSAGES` constant
- Cast WebSocket `seq` to integer to ensure consistent numeric comparison
- Update `useChatScreen` to use `useMessageStore` for immediate local deletion feedback

src/screens/message/components/ChatScreen/useChatScreen.ts

@@ -26,6 +26,7 @@ import { uploadService } from '@/services/upload';
 import { ApiError } from '@/services/core';
 // 【新架构】使用 MessageManager
 import { useChat, useGroupTyping, useGroupMuted, messageManager, callStore } from '../../../../stores';
+import { useMessageStore } from '../../../../stores/message';
 import { groupService } from '@/services/message';
 import { userManager } from '../../../../stores/user';
 import { groupManager } from '../../../../stores/group';
@@ -295,17 +296,14 @@ export const useChatScreen = (props?: ChatScreenProps) => {
   }, [followRestricted, myPrivateSentCount]);
 
   // 加载态语义修正：
-  // isLoadingMessages 在分页加载历史时也会短暂为 true。
-  // 若直接驱动 ChatScreen 的 loading，会导致消息列表被卸载重挂载，触发“回到底部”。
-  // 这里只在“首屏且尚未展示过消息列表”时展示 loading 占位。
+  // 首屏加载：尚未展示过消息列表 且 无消息 → 显示 loading（避免 FlashList 以空 data 挂载后 inverted 布局异常）
+  // 一旦有消息或加载完成（isLoadingMessages 归 false），即解除 loading
   useEffect(() => {
     if (messageManagerMessages.length > 0) {
       hasShownMessageListRef.current = true;
     }
     const shouldShowInitialLoading =
-      !hasShownMessageListRef.current &&
-      isLoadingMessages &&
-      messageManagerMessages.length === 0;
+      !hasShownMessageListRef.current && messageManagerMessages.length === 0 && isLoadingMessages;
     setLoading(shouldShowInitialLoading);
   }, [isLoadingMessages, messageManagerMessages.length]);
 
@@ -1400,16 +1398,15 @@ export const useChatScreen = (props?: ChatScreenProps) => {
   const handleDeleteMessage = useCallback(async (messageId: string) => {
     try {
       await messageService.deleteMessage(messageId);
-      // 从本地状态移除（MessageManager 不会自动处理删除）
-      const updatedMessages = messages.filter(m => m.id !== messageId);
-      // 注意：这里我们依赖 MessageManager 的数据，所以需要通过其他方式刷新
-      // 暂时只删除本地数据库
       await messageRepository.delete(messageId);
+      if (conversationId) {
+        useMessageStore.getState().removeMessage(conversationId, messageId);
+      }
     } catch (error) {
       console.error('删除消息失败:', error);
       Alert.alert('删除失败', '无法删除消息');
     }
-  }, [messages]);
+  }, [conversationId]);
 
   // 清空会话的所有聊天记录
   const handleClearConversation = useCallback(async () => {