refactor(Dockerfile): 将 fastapi 命令替换为 uvicorn 以支持更多配置选项

backend/Dockerfile

@@ -40,4 +40,6 @@ COPY ./app /app/app
 RUN --mount=type=cache,target=/root/.cache/uv \
     uv sync
 
-CMD ["fastapi", "run", "--workers", "1", "app/main.py"]
+# CMD ["fastapi", "run", "--workers", "1", "app/main.py"]
+CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000", "--workers", "1", "--proxy-headers", "--forwarded-allow-ips", "*"]
+