feat: add systemd service unit

deploy/ns8-backup-monitor.service

@@ -0,0 +1,33 @@
+[Unit]
+Description=NS8 Backup Monitor - Alertmanager webhook receiver
+After=network.target
+Documentation=https://repo.lelekaos.com/admin/ns8-backup-monitor
+
+[Service]
+Type=simple
+User=root
+Group=root
+WorkingDirectory=/opt/ns8-backup-monitor
+
+# Configuration
+Environment=PYTHONUNBUFFERED=1
+ExecStart=/usr/bin/python3 -m ns8_backup_monitor --config /etc/ns8-backup-monitor/config.yml
+
+# Restart policy: restart on failure, wait 10s between attempts
+Restart=on-failure
+RestartSec=10s
+StartLimitIntervalSec=120
+StartLimitBurst=5
+
+# Security hardening
+PrivateTmp=true
+ProtectSystem=full
+ReadWritePaths=/var/log
+
+# stdout/stderr go to journald
+StandardOutput=journal
+StandardError=journal
+SyslogIdentifier=ns8-backup-monitor
+
+[Install]
+WantedBy=multi-user.target