Integrate the strict B3 XML, validation, checksum, wildcard, MaxAge, and Origin-null response contract with the C-prime site-replication register from #75.
Preserve fail-closed metadata behavior and rejected-preflight cache variation while keeping legacy-invalid development metadata readable and repairable through a valid CORS PUT or DELETE.
Add combined parser, handler, browser-response, namespace, replication, restart, and legacy-repair regressions, and update the internal design contract.
Refs #75
Signed-off-by: Feng Ruohang <rh@vonng.com>