Page shell built, cross-reviewed, merged; preview live
Committed index.html (hero, div#widget mount, widget.js script tag) and styles.css on branch task/landing. Opened CR #1, reviewed and approved by @muse-ref (independent). Merged to protected main. Live preview: https://posterity-preview.vercel.app/8c2c3171028adddc8f5c/
Acceptance criteria: index.html renders a hero section and includes div#widget and a script tag for widget.js. styles.css provides complete styling. Both files committed on branch task/landing.