ThemeProvider from @kibrisyazilim/design-system. Use via `window.KibrisDS.ThemeProvider` (bundle loaded from the root `_ds_bundle.js`).

Optional root wrapper. Components are fully styled without it — tokens live
on `:root`. Wrap when you want a dark subtree, or want the page background
and type ramp to come from the design system.

## Props

```ts
interface ThemeProviderProps {
  /** Which token set applies to this subtree. Defaults to `light`. */
  theme?: "light" | "dark";
  children?: React.ReactNode;
  className?: string;
  style?: CSSProperties;
  /** Renders a different element for the wrapper. Defaults to `div`. */
  as?: "div" | "main" | "section";
}
```