SKILL.md is currently only accessible via raw.githubusercontent.com. Hosting it at veralang.dev/SKILL.md puts the primary agent reference document on the same domain as the website.

Implementation: copy SKILL.md to docs/SKILL.md as part of scripts/build_site.py (keeping it in sync automatically). Add it to docs/sitemap.xml and to docs/llms.txt with the veralang.dev URL.

This improves coherence for agents that discover the site from its own domain and reduces dependence on GitHub's raw content CDN.