Function sort_rows 

pub fn sort_rows(
    rows: &mut [Row],
    column_ids: &[String],
    sort: Option<&SortSpec>,
)

Sort rows by the given SortSpec, resolving column against the column_ids schema (column id → cell index). An unknown column leaves order unchanged (stable). The sort is stable, so equal keys keep their identity order — deterministic across frontends and in headless/CI.