Add a skill

Create skills/<slug>/SKILL.md with matching YAML name and a description explaining when to select it. Include a concise workflow, verification and useful boundaries. Keep large examples in linked references/ files. Do not require all references to be loaded for every task.

The exporter materializes a native skill directory for each canonical entry, including legacy category topic files. Add a thin website page at assets/mkdocs/skills/<slug>.md for the documentation hook. Test representative tasks and run catalog/link checks. See the contribution guide.