feat: support dify in rag module (#550)

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

src/graph/checkpoint.py

@@ -6,10 +6,12 @@ import logging
 import uuid
 from datetime import datetime
 from typing import List, Optional, Tuple
+
 import psycopg
+from langgraph.store.memory import InMemoryStore
 from psycopg.rows import dict_row
 from pymongo import MongoClient
-from langgraph.store.memory import InMemoryStore
+
 from src.config.loader import get_bool_env, get_str_env