Function lower_surface_node 

pub fn lower_surface_node(
    session: &mut LoweringSession<'_>,
    id: EntityId,
    frame: Transform,
) -> GeometryResult<NodeId>

Lower any supported IfcSurface into a node.

Kept as one entry point so a caller holding only an IfcSurface reference (a half space’s BaseSurface, a swept solid’s ReferenceSurface) does not have to re-dispatch on the concrete subtype itself.