Summary

• Add Tailwind @source for gem/lib/ruby_ui so docs CSS includes classes used by RubyUI components.
• Restores generated utilities that were missed after moving components from web/app/components into the monorepo gem.

Validation

• docker exec -w /workspaces/ruby_ui/docs a40dac6a897a pnpm run build:css
• docker exec -w /workspaces/ruby_ui/docs a40dac6a897a /home/vscode/.local/bin/mise exec ruby@3.4.7 -- bin/rails test