fix(ci): nginx reload 改用 systemctl reload-or-restart，避免空 PID 文件报错

nginx -s reload 依赖 /run/nginx.pid，该文件为空时报 invalid PID number。
改用 systemctl reload-or-restart（经 systemd MAINPID 发 HUP，运行中则 reload、
未运行则启动），并 enable nginx 保证重启后自启。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/ci/deploy.sh

@@ -126,9 +126,13 @@ mkdir -p /opt/jiu/marketing
 rsync -a --delete /tmp/jiu-marketing-new/ /opt/jiu/marketing/
 rm -rf /tmp/jiu-marketing-new
 
-# Update nginx config and reload
+# Update nginx config and reload.
+# reload-or-restart: reload if nginx is running, start it if it's not — avoids
+# `nginx -s reload` failing with "invalid PID number" when nginx isn't running
+# (e.g. after an EC2 reboot where nginx didn't auto-start).
 sudo cp /tmp/nginx-jiu.conf /etc/nginx/conf.d/jiu.conf
-sudo nginx -t && sudo nginx -s reload
+sudo systemctl enable nginx >/dev/null 2>&1 || true   # auto-start on future reboots
+sudo nginx -t && sudo systemctl reload-or-restart nginx
 
 echo "Deploy complete!"
 ENDSSH