v0.16.0

Added

• draugr scan -j/--jobs N — cap how many scan jobs run in parallel (0 = auto, one per
  CPU; 1 = serial). Scanners like Trivy and Semgrep are themselves multi-threaded, so on a
  small or busy machine the default can oversubscribe and slow a run down — -j lets you dial
  it in (down on a laptop, up on a big CI runner). The run's JSON stats now also reports the
  effective concurrency and the deduped count (identical jobs collapsed in-run), so
  you can see the effect and tune from evidence.