add root endpoint for HF Spaces routing

proxy/router.py

@@ -99,6 +99,10 @@ def create_app() -> FastAPI:
     app = FastAPI(title="OpenAI-Compatible API Proxy", version="1.0.0")
     app.include_router(api)
 
+    @app.get("/")
+    async def root():
+        return {"message": "OpenAI API Proxy", "docs": "/v1/health"}
+
     @app.exception_handler(StarletteHTTPException)
     async def http_exception_handler(_request: Request, exc: StarletteHTTPException) -> JSONResponse:
         return JSONResponse(status_code=exc.status_code, content={"error": {"message": exc.detail, "type": "proxy_error"}})