Runs as a host-level systemd timer on CT122 (scripts/discover-devices.sh)
rather than inside the api container, since real ARP entries live in the
host's network namespace, not Docker's bridge network. See
docs/device-discovery.md for the full writeup, including why literal
passive-only ARP reading was dropped (near-empty result in practice).
API reads the resulting JSON file each poll cycle, cross-references
config/hosts.yaml's knownDevices list by IP, and serves /api/devices.
Dashboard gets a new "Network Devices" table.
Closes#9.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
