[mysticmind]

The README was the source of the docs site. Now that the site is live, the guide lives there and the README is a short entry point.

• README: down from about 860 lines to about 100. It keeps the introduction, installation and the platform table, adds a quick start (compiled and run to check its output) and a table of links into the docs, and keeps the license section.
• Docs: the nine guide pages under docs/guide are now ordinary Markdown files, with the content they had when generated from the README. The generator script is reduced to copying the artwork from assets. Each page gets an "Edit this page on GitHub" link.
• Workflows: the docs workflow no longer triggers on README changes, and CI skips changes under docs/.
• Package: the release notes link points at the What's new page of the docs.