address review: ruff format, pyrit[atr] install hint, ModuleNotFoundError guard, regen uv.lock

Per @adrian-gavrila's 2026-06-15 review:
- test: collapse skipif to one line via is_pyatr_installed() helper (mirrors is_opencv_installed); ruff format clean
- scorer: install hint -> pip install pyrit[atr] (docstring + ImportError msg)
- scorer: narrow import guard to ModuleNotFoundError
- regen uv.lock so the pyatr extra resolves in CI

Author: eeee2345