refactor(ProcessPostUseCase, useCursorPagination, useDifferentialPosts): enhance post merging and loading states

- Introduced new methods for merging posts and comments efficiently, improving performance during data updates.
- Updated loading state management in hooks to include initial loading and loading more states for better user feedback.
- Refactored HomeScreen and PostDetailScreen to utilize the new loading states and merging logic, enhancing user experience during data fetching.
- Improved pagination handling in useCursorPagination and useDifferentialPosts to ensure consistent data management across components.

src/stores/messageManager.ts

@@ -1557,8 +1557,8 @@ class MessageManager {
           payload: { conversationId, messages: mergedMessages, source: 'local_history' },
           timestamp: Date.now(),
         });
-        // 异步填充 sender 信息
-        this.enrichMessagesWithSenderInfo(conversationId, mergedMessages);
+        // 性能优化：历史分页仅对新批次做 sender 补全，避免每次扫描全量消息
+        this.enrichMessagesWithSenderInfo(conversationId, formattedMessages);
 
         return formattedMessages;
       }
@@ -1593,8 +1593,8 @@ class MessageManager {
           payload: { conversationId, messages: mergedMessages, source: 'server_history' },
           timestamp: Date.now(),
         });
-        // 异步填充 sender 信息
-        this.enrichMessagesWithSenderInfo(conversationId, mergedMessages);
+        // 性能优化：仅对本次服务端批次做 sender 补全
+        this.enrichMessagesWithSenderInfo(conversationId, serverMessages);
 
         return serverMessages;
       }