Add Drupal headless stack with Next.js frontend

- Add Next.js frontend service (nextjs) with Dockerfile and source
- Update docker-compose.yml: image names, Drupal 11.3.3, nextjs service
- Add docker-compose.override.yml.disabled for dev hot-reload
- Add install-headless-modules.sh for OAuth/JSON:API module setup
- Add README.md with full setup and configuration guide
- Update nginx/Dockerfile and nginx.conf.template for cms. subdomain
- Update drupal/Dockerfile PHP-FPM build args
- Gitignore **/.vscode/ to prevent IDE workspace files from being tracked

drupal/nextjs/components/debug-trigger.tsx

@@ -0,0 +1,16 @@
+"use client"
+
+import { useEffect } from "react"
+
+/**
+ * Triggers the browser debugger when the component mounts.
+ * Only runs in development. Remove when done debugging.
+ */
+export function DebugTrigger() {
+  useEffect(() => {
+    if (process.env.NODE_ENV === "development") {
+      debugger
+    }
+  }, [])
+  return null
+}