add fastapi init

chat/services/chat_service.py

@@ -0,0 +1,15 @@
+# LangChain集成示例
+from langchain_openai import OpenAI
+from dotenv import load_dotenv
+load_dotenv()
+
+class ChatService:
+    def __init__(self):
+        # 这里以OpenAI为例，实际可根据需要配置
+        self.llm = OpenAI(temperature=0.7, api_key='sssss')
+
+    def chat(self, prompt: str) -> str:
+        # 简单调用LLM
+        return self.llm(prompt)
+
+chat_service = ChatService()