Move Playwright, Docker, and package.json into examples/django-react-site

Root directory now contains only the two core packages (django/, react/),
examples/, and top-level docs. All e2e/integration test infrastructure
lives in examples/django-react-site/.

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

examples/django-react-site/playwright.config.ts

@@ -0,0 +1,14 @@
+import { defineConfig } from '@playwright/test'
+
+export default defineConfig({
+    testDir: '.',
+    timeout: 15000,
+    retries: 0,
+    reporter: 'list',
+    use: {
+        baseURL: 'http://localhost:8000',
+    },
+    projects: [
+        { name: 'chromium', use: { browserName: 'chromium' } },
+    ],
+})