Shrinks external-access blip after ISP re-IP (was waiting up to 5min for
the dyndns timer). Adds journal logging so WAN events are auditable.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Flushes stale NAT conntrack on WAN IP change; renews lease then restarts
networkd if internet stays down. ntfy on action. Fixes needing a manual
reboot after the ISP re-IP'd us.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
