Add four new sections: How it Works (4-step onboarding guide), Open Source
(self-host / no lock-in highlights), FAQ (centered accordion), and Footer
(link columns + giant logo with Game of Life animation).
Add scroll-driven features section with 4 tabs (Teammates, Autonomous,
Skills, Runtimes) using IntersectionObserver for auto-switching on scroll.
Replace hero placeholder with actual product screenshot. Remove background
gradient overlay.
