Grouped bars of LOC, tokens, cost and time as a % of the no-skill baseline (lower is leaner/cheaper/faster), plus a separate safety strip (baseline, caveman and ponytail 100%; yagni-oneliner 95%). System-gray palette so it reads on both GitHub themes. The chart commits landed after #158 had already squash-merged, so this brings the chart onto main. Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>