Function build_path_leaf 

fn build_path_leaf(
    path: &Path,
    parent_abs: Transform,
) -> Option<Transformed<Node<VItem>, DAffine3>>

Build a leaf node from a usvg path and the absolute transform of its parent group.

The VItem is built from the raw path segments exactly like the old flat walker did (same segment mapping, fill/stroke parsing, and empty path skipping) — but the path’s placement goes onto the leaf node’s transform instead of being baked into the points.