- Add RFC 8484 DNS wireformat codec and HTTP/2 support (httpx) for
Quad9/OpenDNS DoH providers.
- Quarantine dead, parked, or seized mirrors for the session on hard
failure (DNS errors, connection refused, 410/451, parked pages) while
preserving bypass clearance on live mirrors.
- Add background startup search warmup to prime DNS, elect mirrors, and
pre-solve protection challenges to eliminate cold-start search latency.
- Add comprehensive test suites for DoH wireformat, mirror quarantine,
parked domain detection, and search warmup.
