nb-resolver - DNS-over-HTTPS for Handshake names.

  /dns-query   RFC 8484: GET ?dns=<base64url>, or POST application/dns-message
  /resolve     JSON: GET ?name=<name>&type=<n>

Names below a Handshake TLD are answered from the TLD's Ethereum registry
when minted, and from its nameservers otherwise. Anything else is REFUSED.