Fix code review issues

- Add agent_id parameter to client.add() and use it in mem0_conclude
- Fix inconsistent field access in queue_prefetch_and_get (check both text and memory)
- Remove unused _read_filters() and _write_filters() methods
- Mark prefetch() query parameter as deprecated (was unused)

client.py

@@ -94,17 +94,20 @@ class LocalMem0Client:
         self,
         message: str,
         user_id: Optional[str] = None,
+        agent_id: Optional[str] = None,
         metadata: Optional[Dict] = None,
     ) -> Dict:
         """Add a new memory.
 
         API: POST /add
-        Request: {message, user_id, metadata}
+        Request: {message, user_id, agent_id, metadata}
         Response: {success, memory_id, message}
         """
         payload = {"message": message}
         if user_id:
             payload["user_id"] = user_id
+        if agent_id:
+            payload["agent_id"] = agent_id
         if metadata:
             payload["metadata"] = metadata
         return self._request("POST", "/add", json=payload)