Play Framework

Fix welcome page crash: update CSS references for Tailwind

The welcome.html template still referenced deleted manual.css and
wiki.css files. Updated to use play-tailwind.css instead.

Also fixed CSS distribution: play-tailwind.css must be accessible
through Play's virtual file system, so it's now placed in:
- resources/application-skel/public/stylesheets/ (for user apps)
- modules/docviewer/public/stylesheets/ (for framework pages)

Removed framework/public/ which was not in any search root.
Updated build-css.sh to output to both locations.

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