Function operator_transform 

pub fn operator_transform(
    model: &Model,
    id: EntityId,
    entity: &Entity,
) -> GeometryResult<Transform>

Resolve any IfcCartesianTransformationOperator subtype to a transform.

The attribute is typed as the supertype, so a slot holding one may contain any of the four concrete forms and every consumer would otherwise have to dispatch. Doing it once here keeps the 2D and non-uniform cases from being quietly mishandled at each call site, mirroring crate::resource::placement::axis_placement_transform.