refactor(PostCard, PostCard.legacy): remove legacy PostCard component and update exports

- Deleted the legacy PostCard component to streamline the codebase and improve maintainability.
- Updated exports in PostCard and index files to remove references to the legacy component.
- Adjusted PostCardProps to eliminate legacy properties, ensuring only the new API is supported.
- Enhanced the PostCard component to focus on modern implementation and features.

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

@@ -124,6 +124,8 @@ export const useChatScreen = () => {
   const isProgrammaticScrollRef = useRef(false);
   const suppressAutoFollowRef = useRef(false);
   const isBrowsingHistoryRef = useRef(false);
+  const hasShownMessageListRef = useRef(false);
+  const historyLoadingLockUntilRef = useRef(0);
 
   // 回复消息状态
   const [replyingTo, setReplyingTo] = useState<GroupMessage | null>(null);
@@ -205,9 +207,16 @@ export const useChatScreen = () => {
   // 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“首屏且尚无消息”时展示 loading 占位。
+  // 这里只在“首屏且尚未展示过消息列表”时展示 loading 占位。
   useEffect(() => {
-    setLoading(isLoadingMessages && messageManagerMessages.length === 0);
+    if (messageManagerMessages.length > 0) {
+      hasShownMessageListRef.current = true;
+    }
+    const shouldShowInitialLoading =
+      !hasShownMessageListRef.current &&
+      isLoadingMessages &&
+      messageManagerMessages.length === 0;
+    setLoading(shouldShowInitialLoading);
   }, [isLoadingMessages, messageManagerMessages.length]);
 
   // 【改造】同步 hasMore 状态
@@ -281,10 +290,16 @@ export const useChatScreen = () => {
     enterMarkedKeyRef.current = '';
     suppressAutoFollowRef.current = false;
     isBrowsingHistoryRef.current = false;
+    hasShownMessageListRef.current = false;
+    historyLoadingLockUntilRef.current = 0;
   }, [conversationId]);
 
+  const isHistoryLoadingLocked = useCallback(() => {
+    return Date.now() < historyLoadingLockUntilRef.current;
+  }, []);
+
   const scrollToLatest = useCallback((animated: boolean, force: boolean = false, reason: string = 'unknown') => {
-    if (!force && (suppressAutoFollowRef.current || isBrowsingHistoryRef.current)) return;
+    if (!force && (suppressAutoFollowRef.current || isBrowsingHistoryRef.current || isHistoryLoadingLocked())) return;
     // inverted 列表下，最新消息端对应 offset=0
     isProgrammaticScrollRef.current = true;
     flatListRef.current?.scrollToOffset({
@@ -294,7 +309,7 @@ export const useChatScreen = () => {
     setTimeout(() => {
       isProgrammaticScrollRef.current = false;
     }, animated ? 220 : 32);
-  }, [flatListRef, scrollPositionRef, messages.length]);
+  }, [flatListRef, isHistoryLoadingLocked]);
 
   const isNearBottom = useCallback(() => {
     const scrollY = scrollPositionRef.current.scrollY || 0;
@@ -443,6 +458,8 @@ export const useChatScreen = () => {
 
     // 历史加载期间禁止“新消息自动跟随到底”
     suppressAutoFollowRef.current = true;
+    isBrowsingHistoryRef.current = true;
+    historyLoadingLockUntilRef.current = Date.now() + 3000;
 
     // 保存加载前的滚动位置和内容高度
     const scrollYBefore = scrollPositionRef.current.scrollY;
@@ -464,6 +481,8 @@ export const useChatScreen = () => {
       console.error('加载历史消息失败:', error);
     } finally {
       setLoadingMore(false);
+      // 加载结束后继续保留短暂锁窗，避免布局结算阶段误触自动回底
+      historyLoadingLockUntilRef.current = Date.now() + 800;
     }
   }, [conversationId, hasMoreHistory, loadingMore, loadMoreMessages, messages]);
 
@@ -473,9 +492,10 @@ export const useChatScreen = () => {
   }, []);
 
   const handleReachLatestEdge = useCallback(() => {
+    if (isHistoryLoadingLocked()) return;
     suppressAutoFollowRef.current = false;
     isBrowsingHistoryRef.current = false;
-  }, []);
+  }, [isHistoryLoadingLocked]);
 
   const setBrowsingHistory = useCallback((browsing: boolean) => {
     isBrowsingHistoryRef.current = browsing;
@@ -1221,6 +1241,7 @@ export const useChatScreen = () => {
     longPressMenuVisible,
     selectedMessage,
     selectedMessageId,
+    setSelectedMessageId,
     menuPosition,
     isGroupChat,
     groupInfo,