use root_path when create http server

Author: LiangYang666

src/mcp/server/fastmcp/server.py

@@ -605,6 +605,7 @@ async def run_sse_async(self, mount_path: str | None = None) -> None:
             starlette_app,
             host=self.settings.host,
             port=self.settings.port,
+            root_path=self.settings.root_path,
             log_level=self.settings.log_level.lower(),
         )
         server = uvicorn.Server(config)
@@ -620,6 +621,7 @@ async def run_streamable_http_async(self) -> None:
             starlette_app,
             host=self.settings.host,
             port=self.settings.port,
+            root_path=self.settings.root_path,
             log_level=self.settings.log_level.lower(),
         )
         server = uvicorn.Server(config)