Add a component

A site cannot add a component without changing the theme or its fork: components are theme units, not content files. Adding one never edits a shared index file, because the registry discovers components/<name>/ by listing the folder.

1. Make components/<name>/, using lowercase kebab-case. The folder name is the component's name and the directive an author writes.
2. Add index.ts with the Preact component written with h(), never JSX, and a default export typed by the engine's component contract. The props arrive as strings from the directive's attributes, and the directive's body arrives as rendered HTML.
3. Add style.css only when the component has styles. Read tokens with var(--…), use logical properties, and name classes after the component: the root is <name>, its parts add a suffix such as <name>-title.
4. Add client.ts only when the component needs the browser. It is an island: it ships only on pages that use the component, and every control it enhances starts hidden so the page still reads without JavaScript.
5. Add test/component-<name>.test.ts beside the other component tests. Test the rendered element, each variant, escaping, and the source position.
6. Run npm run check. The registry finds the new folder, and an unknown directive or a missing default export becomes a diagnostic naming the file.

The full rules for a unit are in components/README.md in the repository.