coerce
infix inline fun <Ok, Error> Outcome<Ok, Error>.coerceToFailure(falter: (Ok) -> Error): Failure<Error>
Coerces this Outcome to a Failure.
If already a Failure, returns it unchanged.
If a Success, applies falter to the value and wraps the result in Failure.
Warning: No RaiseScope is provided — exceptions thrown inside falter propagate uncaught. Wrap with outcomeOf if needed.