docs(plugin-eval): add CLAUDE.md, full evaluation framework docs, and README updates

Merge pull request #464 from wshobson/feat/plugin-eval-framework

fix(plugin-eval): address PR review comments

improve(reverse-engineering): deep enhancement of anti-reversing-techniques skill

improve(plugin-eval): tune evaluation-methodology skill for higher score

improve(cicd-automation): deep enhancement of deployment-pipeline-design skill

improve(backend-development): deep enhancement of saga-orchestration skill

improve(backend-development): deep enhancement of architecture-patterns skill

improve(plugin-eval): expand evaluation-methodology skill from stub to comprehensive reference

improve(plugin-eval): add rubrics.md reference for evaluation-methodology skill

improve(plugin-eval): expand evaluation-methodology from stub to comprehensive reference

improve: enhance 5 bottom skills + add technical depth signal

improve: enhance 5 more bottom-scoring skills with triggers, troubleshooting, cross-refs

tune(plugin-eval): improve score differentiation in static analyzer

fix(plugin-eval): address code review findings