Migrate to Tailwind CSS 4, replace all custom CSS and inline styles with utility classes
Installs tailwindcss + @tailwindcss/vite, strips app.css down to Tailwind imports and a
custom scale-up animation, removes the inline <style> block from layout.edge, and converts
every template from inline style attributes to Tailwind utilities.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>