Add scroll-reveal animation utility

[Muneerali199]

Summary

Create a reusable scroll-reveal component that animates elements into view as the user scrolls.

Tasks

• Create components/reveal.tsx using Intersection Observer + framer-motion:
  • Configurable direction: fade-up, fade-left, fade-right, fade-down
  • Configurable delay and duration
  • Staggered children support
• Create hooks/use-in-view.ts for the intersection observer logic
• Add demo sections in app/page.tsx to showcase the reveal effects

Files to change

• components/reveal.tsx (new, ~80 lines)
• hooks/use-in-view.ts (new, ~30 lines)
• app/page.tsx (~50 lines added for demo sections)

Acceptance criteria

• Elements animate in when they enter the viewport
• Works on mobile and desktop
• npm run build succeeds