shadcn/ui

Make this the base layer of any React UI task, then add narrower registries (Dice UI for kanban/data-grid/media, Tailark for marketing sections) on top — they publish against the same registry schema and share the Radix + CSS-variable token model, so they compose without style drift. Always run `init` before `add`, and check components.json aliases; if the project already has a components/ui directory, `add` will overwrite hand-edited files without warning. Do not add a component you can compose from ones already installed — the copy-in model means every `add` is permanent surface area in the repo.

Why it is here. It reset how React UI is distributed — as owned source rather than an imported dependency — and its token conventions are now the lingua franca that a dozen other registries target.