Add a root endpoint to main.py that returns a "Hello World" message.

main.py

@@ -123,3 +123,7 @@ async def chat(request: Query):
     response = re.sub(r'<think>.*?</think>', '', response, flags=re.DOTALL)
     # response = response[4:]
     return {"response": response}
+
+@app.get("/")
+async def root():
+    return {"message": "Hello World"}