Move desktop and e2e into examples/ directory

- desktop/ → examples/django-react-desktop-app/
- e2e/ → examples/django-react-site/
- example/ → examples/django-react-site/backend/
- Update Dockerfile.test, Makefile, playwright config, and
  django.config.mjs path references

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

examples/django-react-site/harness/src/main.tsx

@@ -0,0 +1,13 @@
+import { createRoot } from 'react-dom/client'
+import { DjangoContext } from './api/generated.django'
+import { Fixtures } from './fixtures'
+
+function App() {
+    return (
+        <DjangoContext baseUrl="/api/mizan">
+            <Fixtures />
+        </DjangoContext>
+    )
+}
+
+createRoot(document.getElementById('root')!).render(<App />)