Function verify_trusted_reagent_jekt 

pub fn verify_trusted_reagent_jekt(
    key_id: &str,
    msgid: &str,
    source_agent: &str,
    target_agent: &str,
    ts_secs: i64,
    message: &str,
    sig_b64: &str,
) -> bool

The verification result a receiver records as reagent_verified: the signature checks out AND its key is the trusted production key. A signature under any other registered key is not a verified sender.