Play Framework

Restyle welcome page with Tailwind CSS

The welcome_en.html template still used old docviewer CSS classes
(wrapper, docSidebar, pageContent, wikistyle) from the deleted
manual.css/wiki.css. Rewrote with Tailwind utility classes:

- Two-column flex layout with sidebar and content area
- Dark code blocks with rounded corners
- Inline code with gray background pills
- Green accent links matching Play brand color
- Green top border on body
- Clean typography hierarchy

Regenerated play-tailwind.css for new utility classes.

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