Function compare 

pub fn compare(
    old: &[Value],
    new: &[Value],
    ignore_line_drift: bool,
    rule_renames: Option<&HashMap<String, String>>,
) -> DiffReport

Compares two spec-001 violation lists. Mirrors diff.py::compare (spec 016 contract C-2). rule_renames isn’t exposed by the jss-lint diff CLI surface today (Python’s diff_cmd doesn’t wire a --rule-renames flag either) — kept as a parameter for API parity with the Python function.