Function offset_torus_face 

pub fn offset_torus_face(
    solid: &BrepSolid,
    face_id: u64,
    distance: f64,
) -> Result<BrepSolid, String>

Push a toroidal face by changing its tube radius. Boundary edges must be intrinsic to this face; neighbour-trimmed rims require re-intersection and are refused. The carrier retains its knot vectors, weights, and UV basis, keeping pcurves valid. Iso boundaries rebuild exactly; other self-incident trims use crate::image_curve.