DNS-Based Service Discovery for Encrypted DNS Services

This document defines a DNS-Based Service Discovery (DNS-SD) mechanism for discovering encrypted DNS services in local networks. It specifies new service types (_dot, _doh, _doq) and associated service parameters to enable zero-configuration discovery of DNS over TLS (DoT), DNS over HTTPS (DoH), and DNS over QUIC (DoQ) resolvers. The mechanism works over both multicast DNS (mDNS) and unicast DNS- SD, addressing critical privacy gaps in local networks while maintaining backward compatibility with RFC 6763. This document leverages SVCB and HTTPS resource records (RFC 9460) for parameter negotiation, with TXT records provided for compatibility with legacy implementations.