Detect Python/Node/PM2 on deploy (install only if missing); uninstall removes /opt/eth_hedge_sim.

Keep .env and DB backup under /root/backups before deleting the install directory.

Co-authored-by: Cursor <cursoragent@cursor.com>

deploy/lib/update.sh

@@ -19,6 +19,8 @@ main_update() {
     die "安装不完整，请先执行「1) 一键部署」"
   fi
 
+  step "更新 — 环境检测 (缺则装，有则跳过)"
+  ensure_system_deps
   step "更新 比特骆驼自动化对冲系统 (git pull + 构建 + pm2 reload)"
   bash "${REPO_ROOT}/deploy/pull_and_restart.sh"
   verify_health || true