python -m faircode.figures has no test #1007

Where: faircode/figures.py (main() and the __main__ guard, lines 98-115), tests/test_figures.py.

Current gap: generate_figures() is tested, but the command-line wrapper that parses --results-dir and --metric, prints "Figures written to ...", and is the documented way to regenerate the plots is never run, so a renamed argument or a broken default would only show up when someone regenerates the figures by hand.

Repro:

$ python3 -m pytest tests -q -m "not slow" --cov=faircode --cov-report=term-missing | grep figures.py
faircode/figures.py ... 115

Suggested approach: call main(["--results-dir", str(tmp_path), "--metric", ...]) against a small results fixture (matplotlib is already required by the existing figure tests) and assert the output line and the written files; add an unknown-metric case.