- Add SSH-based health check for pvestatd D-state detection on Proxmox host
(heal via cgroup move + lock file removal + reset-failed)
- Add SSH-based disk check for OPNsense VM (threshold 75%, auto-cleanup)
- knowledge/fixes.json: add 48 training fixes including post-reboot DNS
recovery (fix-046), cloudflared DNS-wait boot fix (fix-047), and
vzdump load-crash scenario with recovery steps (fix-048)
