零 Node 部署、超级管理员，并完善本地构建发布文档。

- FastAPI 单进程托管 frontend/dist，systemd 替代 PM2

- 超级管理员 admin、注册开关与用户管理

- README/DEPLOY/USAGE 说明：改代码须本地构建 dist 后 push，服务器 update.sh

- 提交 frontend/dist 与 build-frontend 脚本

deploy/grade-archive.service

@@ -0,0 +1,15 @@
+[Unit]
+Description=Secondary School Grade Archive
+After=network.target postgresql.service
+Wants=postgresql.service
+
+[Service]
+Type=simple
+WorkingDirectory=/opt/secondary-school-grade-archive
+ExecStart=/opt/secondary-school-grade-archive/deploy/start.sh
+Restart=always
+RestartSec=5
+EnvironmentFile=-/opt/secondary-school-grade-archive/.env
+
+[Install]
+WantedBy=multi-user.target