refactor(application): remove unused sync service methods (#6417)

app/application/messaging/chat.py

@@ -77,20 +77,6 @@ class AsyncAgentChatRepository(Protocol):
         """同步读取服务端会话。"""
         ...
 
-    def save_display_messages(
-        self,
-        session_id: str,
-        user_id: Optional[str] = None,
-        messages: Optional[list[dict]] = None,
-        username: Optional[str] = None,
-        channel: Optional[Any] = None,
-        source: Optional[str] = None,
-        original_chat_id: Optional[str] = None,
-        client_session_id: Optional[str] = None,
-    ) -> Optional[Any]:
-        """同步保存用户可见会话消息。"""
-        ...
-
 
 class SyncAgentChatRepository(Protocol):
     """仅包含 Agent 编排所需同步持久化方法的适配器端口。"""
@@ -267,31 +253,6 @@ class AgentChatService:
         record = self._repository.get(session_id=session_id)
         return self._project(record) if record is not None else None
 
-    def save_display_sync(
-        self,
-        *,
-        session_id: str,
-        user_id: Optional[str] = None,
-        messages: Optional[list[dict]] = None,
-        username: Optional[str] = None,
-        channel: Optional[Any] = None,
-        source: Optional[str] = None,
-        original_chat_id: Optional[str] = None,
-        client_session_id: Optional[str] = None,
-    ) -> Optional[AgentChatRecord]:
-        """同步保存用户可见消息并返回最新投影。"""
-        record = self._repository.save_display_messages(
-            session_id=session_id,
-            user_id=user_id,
-            messages=messages,
-            username=username,
-            channel=channel,
-            source=source,
-            original_chat_id=original_chat_id,
-            client_session_id=client_session_id,
-        )
-        return self._project(record) if record is not None else None
-
     @staticmethod
     def can_access(
         record: AgentChatRecord,