## What & why
Removes the `twenty-sdk/ui` reexport. Apps now use Twenty UI by
installing
[`twenty-ui@1.0.0-alpha.1`](https://www.npmjs.com/package/twenty-ui/v/1.0.0-alpha.1)
from npm and importing its subpaths directly. The reexport re-exported
types that didn't resolve, forcing typecheck workarounds.
## Changes
- **twenty-sdk**: delete `src/ui/index.ts`, drop the `./ui` export,
remove it from the browser vite build, and rewire the CLI manifest-mock
to `twenty-ui` (`.css` falls through to the empty-CSS loader).
`twenty-ui` stays a devDependency for the CLI fixture tests.
- **Renderer + create-twenty-app template**: import from `twenty-ui`
subpaths; the template pins `twenty-ui@1.0.0-alpha.1`.
- **Docs**: new "Using Twenty UI components" section (install + subpath
imports + `useTheme()` for theme tokens), codex references, and the
cross-doc-contract validator.
The `twenty-for-twenty` / `twenty-slack` example apps are intentionally
left on `twenty-sdk/ui`: they consume the published SDK (which still
ships `./ui`), and `twenty-ui@1.0.0-alpha.1` requires react 19 + a
`monaco-editor` peer the react-18 apps can't satisfy. They migrate once
the SDK is republished.
Raphaël Bosi