Keep miekg/dns's default request policy unless a plugin explicitly registers an additional opcode. Aggregate the policy at the listener, then enforce it again after zone routing so mixed server blocks on one socket remain isolated.
Apply the same policy to UDP, TCP, and DNS-over-TLS while preserving TSIG verification and the one-question requirement.
Signed-off-by: houyuwushang <liuluoqianqiu@outlook.com>
Add comprehensive tests for multiple components including server blocks
inspection, configuration handling, DoH/DoQ writers, and server startup
functions. Increases overall test coverage from 27% to 38.4% with
particular focus on register.go, https.go, quic.go, and config.go.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
