feat: add evals for page-cro, copywriting, and seo-audit skills
5 eval prompts per skill testing realistic user scenarios:
- page-cro: landing page audit, pricing page, homepage, feature page, redesign regression
- copywriting: homepage copy, headline rewrite, pricing page, landing page, CTA improvement
- seo-audit: full site audit, ranking diagnosis, migration recovery, e-commerce technical, blog content
Follows the skill-creator eval format with prompt + expected_output assertions.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>