The http.security_txt rule reported OK for any 200 response with a
non-empty body, so a soft-404 (status 200 + HTML body) served for
/.well-known/security.txt was misread as "published".
Capture the response Content-Type and count the RFC 9116 required
fields (Contact, Expires) in the body. OK now requires text/plain with
at least one Contact and exactly one Expires; a non-conforming 200
yields a new Warn http.security_txt.invalid explaining the defect.
Redirects are still followed and the final response is validated, per
RFC 9116 §3.
