修改引用逻辑，修改长期记忆bug

rag_core/retriever_factory.py

@@ -2,14 +2,7 @@
 from langchain_core.embeddings import Embeddings
 from langchain_classic.retrievers import ParentDocumentRetriever
 from langchain_text_splitters import RecursiveCharacterTextSplitter
-from rag_indexer.splitters import SplitterType, get_splitter
-import asyncio
-import logging
-from dataclasses import dataclass, field
-from pathlib import Path
-from typing import List, Union, Optional, Any, Dict, Tuple
-from httpx import RemoteProtocolError
-from langchain_core.documents import Document
+from typing import Optional
 from langchain_core.embeddings import Embeddings
 from langchain_core.stores import BaseStore
 from langchain_text_splitters import RecursiveCharacterTextSplitter, TextSplitter
@@ -17,7 +10,6 @@ from langchain_classic.retrievers import ParentDocumentRetriever
 
 from rag_core import LlamaCppEmbedder, QdrantVectorStore, create_docstore
 
-
 def create_parent_retriever(
     collection_name: str = "rag_documents",
     embeddings: Optional[Embeddings] = None,