Split pairing home address from dashboard URL
Persist pairing.home_address as a bare IPv4 listener address, keep Convey client resolution loopback-only, and converge network status/pair-start LAN evidence through a shared pure resolver. Remove the settings host-url mutation surfaces, expose dashboard_url for Convey status, and add the one-shot migration from legacy pairing.host_url.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>