fix: 修复RAG工具关键方法缺少返回值导致的失败问题

- add_document()方法添加return True,修复添加文档失败的bug
- reset_database()方法添加return True,修复重置失败的bug
- reset_database()重新创建集合时添加embedding_function参数
- 修复get_or_create_collection导致的embedding函数冲突问题
- 优化集合初始化逻辑,先尝试获取已存在集合再创建新集合

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/bidmaster/tools/rag.py

@@ -43,11 +43,18 @@ class RAGTool:
         self.embedding_function = self._get_embedding_function()
 
         # 获取或创建集合
-        self.collection = self.client.get_or_create_collection(
-            name=self.settings.collection_name,
-            embedding_function=self.embedding_function,
-            metadata={"description": "BidMaster知识库"}
-        )
+        try:
+            # 尝试获取已存在的集合
+            self.collection = self.client.get_collection(
+                name=self.settings.collection_name
+            )
+        except Exception:
+            # 集合不存在,创建新集合
+            self.collection = self.client.create_collection(
+                name=self.settings.collection_name,
+                embedding_function=self.embedding_function,
+                metadata={"description": "BidMaster知识库"}
+            )
 
         # 初始化文本分割器
         self.text_splitter = RecursiveCharacterTextSplitter(
@@ -74,6 +81,8 @@ class RAGTool:
         # 添加到向量数据库
         self._add_chunks_to_db(chunks, file_path)
 
+        return True
+
     def search(self, query: str, k: int = 5) -> list[dict[str, Any]]:
         """搜索相关内容"""
         results = self.collection.query(
@@ -121,9 +130,12 @@ class RAGTool:
         # 重新创建集合
         self.collection = self.client.get_or_create_collection(
             name=self.settings.collection_name,
+            embedding_function=self.embedding_function,
             metadata={"description": "BidMaster知识库"}
         )
 
+        return True
+
     def _load_document(self, file_path: Path) -> list[Document]:
         """根据文件类型加载文档"""
         suffix = file_path.suffix.lower()