The test budget: mesh-host is over 500 unit tests, so the three tests
added for ADR 0593 §6 and §7 are paid for by folding the private
network's hub refusals, its MTU cases and its no-self-peer check into
table-driven tests, each case kept.
Claude-Session: https://claude.ai/code/session_01NcbgfJ9Gum47zkFKWRaovL