feat(homepage): increase hero abacus size for better visibility

Increase scale values across all breakpoints, especially on mobile:
- Mobile (base): scale(2) → scale(3) (50% increase)
- Medium screens (md): scale(3) → scale(4.5) (50% increase)
- Large screens (lg): scale(4) → scale(6) (50% increase)

The abacus now fills more of the available hero space without
clipping, improving visual impact and usability on all devices.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/web/src/components/HeroAbacus.tsx

@@ -131,7 +131,7 @@ export function HeroAbacus() {
       >
         <div
           className={css({
-            transform: { base: 'scale(2)', md: 'scale(3)', lg: 'scale(4)' },
+            transform: { base: 'scale(3)', md: 'scale(4.5)', lg: 'scale(6)' },
             transformOrigin: 'center center',
             transition: 'all 0.5s cubic-bezier(0.4, 0, 0.2, 1)',
           })}