Function classify_session 

pub fn classify_session(
    record: Option<(SubjectId, SessionId, u64)>,
) -> SessionValidationOutcome

Classify a session lookup from the store’s query result.

record is None when the store found no active row for the given lookup key (expired, revoked, or never issued). When Some, the tuple is (subject_id, session_id, expires_at_unix_secs).