Function enforce 

pub fn enforce(
    outcome: Result<CustomerState, CleanLibraryError>,
) -> Result<(), GateError>

enforce() — RAISES style for gate use. Ok(()) iff clean-to-proceed.

• a non-clean COMPLETED assessment → Err(GateError::Blocked) (the same outcome verdict returns as a value, re-expressed as a raise so a gate can ?-propagate it);
• a couldn’t-assess → Err(GateError::NotAssessed), carrying the original error.

Fail-closed by construction: because Assessment::is_allowed is true only for the Clean tier, a NotYetAssessed / RangeNotResolved refuses here just like a Malicious does — “not assessed” can never pass the gate.