feat: add config/history management to core layer

- Add GET_CONFIG, SET_CONFIG, GET_HISTORY, SAVE_HISTORY to BackendServer
- Update BackendClient with get_config, get_message_history, save_message_history
- All API key and message history now stored in core layer

core/client.py

@@ -1,7 +1,7 @@
 import threading
 from typing import Any, Dict
 
-from .server import BackendServer
+from .server import BackendServer, MessageType
 
 
 class BackendClient:
@@ -20,8 +20,42 @@ class BackendClient:
             self._request_counter += 1
         return self._server.execute_tool(tool_name, arguments, timeout)
 
-    def update_config(self, api_key: str, base_url: str = "https://api.deepseek.com") -> None:
-        self._server.update_config(api_key, base_url)
+    def update_config(self, api_key: str, base_url: str = "https://api.deepseek.com") -> Dict[str, Any]:
+        return self._send_request(MessageType.SET_CONFIG, {"api_key": api_key, "base_url": base_url})
+
+    def get_config(self) -> Dict[str, str]:
+        result = self._send_request(MessageType.GET_CONFIG, {})
+        return result.get("data", {"api_key": "", "base_url": "https://api.deepseek.com"})
+
+    def get_message_history(self) -> list:
+        result = self._send_request(MessageType.GET_HISTORY, {})
+        return result.get("data", {}).get("history", [])
+
+    def save_message_history(self, messages: list) -> None:
+        self._send_request(MessageType.SAVE_HISTORY, {"messages": messages})
+
+    def _send_request(self, message_type: MessageType, payload: Dict[str, Any]) -> Dict[str, Any]:
+        import queue
+        request_id = f"{id(self)}"
+        response_queue = queue.Queue()
+        
+        from .server import BackendRequest
+        request = BackendRequest(
+            request_id=request_id,
+            message_type=message_type,
+            payload=payload,
+            response_queue=response_queue
+        )
+        
+        self._server._request_queue.put(request)
+        
+        try:
+            response = response_queue.get(timeout=5.0)
+            if not response.success:
+                raise Exception(response.error)
+            return {"success": True, "data": response.data}
+        except queue.Empty:
+            return {"success": False, "error": "timeout"}
 
     def shutdown(self) -> None:
         self._server.shutdown()