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>

README.md

@@ -276,7 +276,7 @@ cd react && npm test
 
 # E2E integration tests (real browser, real backend)
 docker compose -f docker-compose.test.yml up -d
-cd e2e/harness && npm install && npx mizan-generate && npx vite --port 5174 &
+cd examples/django-react-site/harness && npm install && npx mizan-generate && npx vite --port 5174 &
 npx playwright test
 
 # All at once
@@ -289,8 +289,8 @@ make test-all
 mizan/
   django/          Python package (mizan)
   react/           TypeScript package (@rythazhur/mizan)
-  example/         Integration test backend (Docker)
-  desktop/         PyWebView desktop test app
-  e2e/             Playwright E2E tests + React harness
+  examples/
+    django-react-site/         E2E tests, React harness, Django backend
+    django-react-desktop-app/  PyWebView desktop app
   Makefile         Test orchestration
 ```