Function compare_pseudo_header_order 

pub fn compare_pseudo_header_order(observed: &[String]) -> HeaderOrderMatch

Compare an observed pseudo-header order against the Chrome 136 reference.

The reference is the only stable observation we have for pseudo-headers; mismatches fall into “wrong order” rather than “wrong set” because the set is fixed by the HTTP/2 spec.

Exposed for callers that want to reuse the same matcher the scoring logic uses.