Behaviour + demo macro for per-component documentation modules.
A doc module supplies what reflection can't: a description, the slot example
the configurator renders, optional initial prop overrides, a one-line
preview/1 that spreads the live prop map into the component, and curated
demos. Demos are authored as heredoc HEEx strings and compiled at build
time — the same string is rendered and displayed, so they can't drift, and a
typo fails compilation rather than the browser.
Summary
Functions
Registers a curated demo. source must be a heredoc string literal (no
interpolation) — it is compiled to a render function at build time and kept
verbatim for display. opts may include :description.