Build and dev scripts

- Development CSS watch:
  npm run dev:css

- Production build (CSS + copy Flowbite & HTMX JS to appui/assets/js):
  npm run build

- Manually copy Flowbite JS (if needed):
  npm run copy:flowbite
- Manually copy HTMX JS (if needed):
  npm run copy:htmx

Notes
- The build step copies:
  - node_modules/flowbite/dist/flowbite.min.js -> appui/assets/js/flowbite.min.js
  - node_modules/htmx.org/dist/htmx.min.js -> appui/assets/js/htmx.min.js
- The iframe (BEEZUI_ENTRYPOINT) loads these from appui/assets/js, so you don't need to serve node_modules in production.