R20C-R08 rollback guidance

#!/usr/bin/env bash
# Manual rollback guidance for R20C. Run only after explicit operator decision.
# Snapshot: r20c-pre-0720-084006
# Backup: /root/router-egress-r20c-backup-20260720-084006
ssh pve-mgts "ssh -T -i /root/.ssh/pve_to_openwrt_mgts_ed25519 root@10.71.100.2 'R20C_BACKUP_DIR=/root/router-egress-r20c-backup-20260720-084006 sh -s'" < scripts/vm101-rollback.sh