iCloud Private Relay hides iPhones' real public IP, breaking
IP-based LAN grouping. Devices now detect their local IP
(192.168.x.x) via WebRTC ICE candidates and send it to the
server. The server groups devices by local subnet as a fallback
when public IPs differ.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
