Function to_wire 

pub fn to_wire(
    model: &ArchModel,
    project_root: &Path,
    snapshots: &HashMap<PathBuf, String>,
) -> WireArchModel

Lower the whole model. A node (or member, or edge) whose own location can’t be resolved (see wire_loc above) is dropped rather than sent with a bogus location — click-to-code must never open the wrong file.