[Examples] Add a stupid 404 page (#2694)

Use a 404 Page.

### Change Type

- [x] `documentation` — Changes to the documentation only[^2]

apps/examples/src/index.tsx

@@ -24,6 +24,10 @@ const basicExample = gettingStartedExamples.value.find((e) => e.title === 'Basic
 if (!basicExample) throw new Error('Could not find basic example')
 
 const router = createBrowserRouter([
+	{
+		path: '*',
+		element: <div>404</div>,
+	},
 	{
 		path: '/',
 		lazy: async () => {