重构代码，实现相对导入

rag_indexer/index_builder.py

@@ -6,10 +6,14 @@
 
 import asyncio
 import logging
-from dataclasses import dataclass, field
+import sys
 from pathlib import Path
+from dataclasses import dataclass, field
 from typing import List, Union, Optional, Any, Dict
 
+# 添加 backend 目录到路径以导入 rag_core
+sys.path.insert(0, str(Path(__file__).parent.parent / "backend"))
+
 from httpx import RemoteProtocolError
 from langchain_core.documents import Document
 from langchain_core.embeddings import Embeddings
@@ -17,8 +21,8 @@ from langchain_core.stores import BaseStore
 from langchain_text_splitters import RecursiveCharacterTextSplitter, TextSplitter
 from qdrant_client.http.exceptions import ResponseHandlingException
 
-from rag_indexer.loaders import DocumentLoader
-from rag_indexer.splitters import SplitterType, get_splitter
+from .loaders import DocumentLoader
+from .splitters import SplitterType, get_splitter
 from rag_core import LlamaCppEmbedder, QdrantVectorStore, create_docstore, create_parent_retriever
 
 logger = logging.getLogger(__name__)