Site MD skill: what it does and how to install it

What it does. Analyses a project brief or existing site content and writes .stitch/SITE.md for the Stitch Build Loop. It captures the project's identity, audience and visual direction, maps the file structure and sitemap, and groups development tasks by priority.

When to use it. When starting a Stitch project or organising requirements into a shared guide for ongoing build iterations. It can use a Stitch Project ID if one is available.