fix: restore original import order to satisfy ruff isort

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: scale-ballen

src/agentex/lib/sdk/fastacp/base/base_acp_server.py

@@ -10,8 +10,8 @@
 
 import uvicorn
 from fastapi import FastAPI, Request
-from fastapi.responses import StreamingResponse
 from pydantic import TypeAdapter, ValidationError
+from fastapi.responses import StreamingResponse
 from starlette.types import ASGIApp, Receive, Scope, Send
 
 from agentex.lib.types.acp import (