Extends monitoring to the two bare-metal boxes Proxmox can't see.
Uses a dedicated ed25519 key with a forced authorized_keys command
(see docs/ssh-collector-key-setup.md) so a leaked key can only ever
run the fixed read-only stats script, never arbitrary commands.
CPU is approximated from 1-min load average / core count (a true
utilization % would need two /proc/stat samples).
Closes#8.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>