Block 6to4/Teredo/NAT64-local/site-local/benchmarking/reserved
ranges from the IANA registries (families, not decoded embeds).
Guard.DenyPrefixes / -deny-prefix covers hairpin WAN /32s; home
addresses stay on-box, not in git. Control is tcp/tcp4/tcp6 only.
Go service with /healthz, SSRF guard (parse + resolve-all + Control),
exhaustive tests, NixOS module, and Makefile as source of truth for
build flags. nix flake check runs make test lint.
kyle