Parameterize the in-cluster split-horizon target as GATEWAY_VIP (R-ENV-02): base
default = dev L2-announced Gateway VIP (10.73.0.240, first IP of the Cilium LB pool).
coredns-custom answers *.home.keithjackson.dev with ${GATEWAY_VIP} so the unified graph
holds across dev/prod via cluster-vars only. Prod overlay carries a TODO to set the prod
LAN VIP alongside the prod L2 pool range when hardware is built.
Co-Authored-By: Claude Opus 4.8 <[email protected]>