refactor(chat): remove guest history synchronization

src/data/repositories/chat_repository.ts

@@ -10,7 +10,6 @@ import type {
 import type {
   ChatHistoryResponse,
   ChatPreviewsResponse,
-  ChatSyncRequest,
   ChatMessage,
   ChatSendResponse,
   UnlockHistoryResponse,
@@ -63,13 +62,6 @@ export class ChatRepository implements IChatRepository {
     return this.remote.getPreviews(options);
   }
 
-  async syncGuestHistory(
-    request: ChatSyncRequest,
-    options?: ChatRequestOptions,
-  ): Promise<Result<void>> {
-    return this.remote.syncGuestHistory(request, options);
-  }
-
   /** 解锁单条历史付费 / 私密消息。 */
   async unlockPrivateMessage(
     input: UnlockPrivateMessageInput,