Xiaomi miIO/MIoT devices silently ignore UDP packets from source IPs
outside their subnet. Added SRCNAT masquerade rule documentation for
VLAN 10 → VLAN 30 on UDP 54321, enabling HA local control of air
purifiers and other Xiaomi WiFi devices.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>