Function outcome_key_id_from_snapshot 

pub(crate) fn outcome_key_id_from_snapshot<'a>(
    caller_key_rec: Option<&'a Arc<KeyRecord>>,
    authed_key_at_precheck: Option<&'a Arc<KeyRecord>>,
) -> Option<&'a str>

Compute the audit key id from the same snapshot used by the write precheck. This prevents SIGHUP reload between daemon dispatch and audit emission from re-attributing an outcome to the startup key or <none>.