Function evaluate 

pub async fn evaluate(
    conn: &mut PgConnection,
    stuck: &[StuckRegistrationCount],
    depths: &[(CreditRegistrationState, i64)],
) -> ModelResult<CreditRegistrationHealth>

Runs every rule and ranks what it found.

stuck and depths are passed in because the caller already reads both aggregates, the two most expensive reads in the request. depths is the live count per state, superseded rows excluded, as credit_registrations::count_by_state returns it.