Patch: publish every note

This whole documentation site is public. Rather than add free: true to the frontmatter of every note by hand, one patch marks all Markdown free — except the demo/ vault, which keeps its own access rules.

This note IS the patch: the rule below is read from its jsonnet block, and the file is itself a live example of the feature. See frontmatter-patches for how patches work.

{ free: true }