Function preview_refactor 

pub fn preview_refactor(
    catalog: &OntologyCatalog,
    request: &RefactorRequest,
    document_overrides: &HashMap<PathBuf, String>,
    workspace_roots: &[PathBuf],
) -> Result<RefactorPlan>

Preview a refactor. Client-supplied paths (target_file / output_file) are jailed under workspace_roots before any filesystem read.