DNS A records now return the WireGuard server IP (10.0.0.1) instead of
Docker bridge VIPs so cross-cell peers resolve service names correctly
regardless of their bridge subnet. DNAT rules (wg0:53→cell-dns:53 and
wg0:80→cell-caddy:80) are applied at startup. Caddy routes by Host header,
eliminating the Docker bridge subnet conflict. Firewall cell rules allow
DNS and service (Caddy) traffic from linked cell subnets. Split-tunnel
AllowedIPs now dynamically includes connected-cell VPN subnets and drops
the 172.20.0.0/16 range. Peers with route_via set now receive full-tunnel
config (0.0.0.0/0) so all their traffic exits via the remote cell.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>