// Onrail UI — React primitive layer over brand/components.css.
//
// Each primitive is a thin wrapper: composes a className, spreads extra
// props, forwards refs. NO new visual logic — all paint comes from the
// CSS layer. Adding a new primitive here without a backing CSS class is
// a design-system smell.
//
// Load as:
//
//
// Components are exported to `window` so other Babel-transpiled scripts
// in the same page can use them (each