style: premium dark SaaS design system (Geist, tokens, surfaces)

Add production essentials: rate limits, legal pages, Clerk welcome webhook, footer links

style: widen in-app UI from 720px to 960px for a roomier layout

style: modernize design tokens, surfaces, and dark-mode coverage across app shell, scorer, and footer

Fix shell animation scoping and merge primary focus dark rule

Add subtle global motion: tokens, transitions, shell entrance

Add footer copyright line (All rights reserved)

Restyle studio branding as minimal bottom strip with copy link

Add Hecatoncheires Product Studio branding, global shell, and Support page