Function run_in_dirs_parallel 

pub fn run_in_dirs_parallel(
    jobs: usize,
    items: &[(String, PathBuf)],
    program: &str,
    args: &[String],
) -> Vec<CapturedRun> 

Run program args… in each (name, dir) of items with up to jobs concurrent workers, capturing each one’s output. Returns one (ExecOutcome, captured_output) per item in input order (not completion order), so the caller prints deterministic per-worktree blocks regardless of which finished first. jobs is clamped to [1, items.len()].