Dev server renders unstyled UI: no Tailwind/PostCSS in host scaffold #78

Fixed in #87 (duplicate of #82). The scaffold now ships tailwindcss@^4 + @tailwindcss/vite@^4 in client_app/package.json, registers the plugin in vite.config.ts, and client_app/styles.css imports the UI globals + module @source globs. Verified in framework/cli/simple_module_cli/templates/host/client_app/.