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/stores/messageManagerHooks.ts

@@ -55,7 +55,10 @@ export function useConversations(): UseConversationsReturn {
 
     // 冷启动兜底：延迟做一次强制刷新，避免首次因时序问题拿到空列表
     const coldStartSyncTimer = setTimeout(() => {
-      messageManager.fetchConversations(true).catch(error => {
+      messageManager.requestConversationListRefresh('hooks-initial-refresh', {
+        force: true,
+        allowDefer: true,
+      }).catch(error => {
         console.error('[useConversations] 冷启动强制刷新失败:', error);
       });
     }, 1200);
@@ -67,7 +70,10 @@ export function useConversations(): UseConversationsReturn {
   }, []);
 
   const refresh = useCallback(async () => {
-    await messageManager.fetchConversations(true);
+    await messageManager.requestConversationListRefresh('hooks-manual-refresh', {
+      force: true,
+      allowDefer: false,
+    });
   }, []);
 
   const loadMore = useCallback(async () => {
@@ -530,7 +536,10 @@ export function useMessageListRefresh(): UseMessageListRefreshReturn {
 
     setIsRefreshing(true);
     try {
-      await messageManager.fetchConversations(true);
+      await messageManager.requestConversationListRefresh('hooks-load-more-fallback', {
+        force: true,
+        allowDefer: false,
+      });
     } catch (error) {
       console.error('[useMessageListRefresh] 刷新失败:', error);
     } finally {