Function is_block_local_face_sturdy 

pub fn is_block_local_face_sturdy(
    boxes: &[BlockLocalAabb],
    direction: Direction,
    support_type: SupportType,
) -> bool

Checks whether an owned union of block-local boxes is sturdy on a face.

Static registry shapes use VoxelShape, while dynamic blocks resolve their boxes from live world data. Both representations use the same face coverage rules.