chore(root): archive examples into tech-preview (#315)

packages/__tech-preview__/examples/react/src/main.tsx

@@ -0,0 +1,10 @@
+import { StrictMode } from 'react';
+import { createRoot } from 'react-dom/client';
+
+import App from './App';
+
+createRoot(document.getElementById('root')!).render(
+  <StrictMode>
+    <App />
+  </StrictMode>,
+);