pub fn pair<'a>(
secret: Option<&'a str>,
kid: Option<&'a str>,
) -> Result<Option<(&'a str, &'a str)>, MissingHalf>Expand description
Classify a possibly-half-configured (secret, kid) pair.
Ok(None) = nothing configured, which is a legitimate state everywhere
this is used (a host that does not sign, an operator without a break-glass
key to hand). Err = exactly one half present, which is never intentional
and must not silently fall back to unsigned: signing under a mismatched or
invented id produces command_signature_invalid fleet-wide, which is the
forgery alarm raised by a configuration mistake.