- Ethernet watchdog: background task polls /sys/class/net every 5s, detects
cable plug-in on disabled interfaces and auto-enables with DHCP
- interface_down endpoint now refuses to disable the only active interface
(returns 409), preventing accidental lockout
- Frontend shows the error message instead of silently failing
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
