feat: add bare-metal deployment configs for Proxmox/LXC

Provide ready-to-use nginx, systemd, and environment configs
for bare-metal installs. Community Proxmox scripts currently
sed-hack the Docker nginx.conf with patterns that don't match,
causing broken pid/log paths and tmpfiles issues on reboot.

deploy/termix.service

@@ -0,0 +1,16 @@
+[Unit]
+Description=Termix Backend
+After=network.target guacd.service
+Wants=guacd.service
+
+[Service]
+Type=simple
+User=root
+WorkingDirectory=/opt/termix
+EnvironmentFile=/opt/termix/.env
+ExecStart=/usr/bin/node /opt/termix/dist/backend/backend/starter.js
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target