fix(levels): increase container height to prevent abacus clipping

Increased the main level display container height from 700px to 900px
to provide more vertical space for the abacus display.

This prevents the top and bottom of the abacus from being clipped,
especially for levels with larger column counts.

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

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

apps/web/src/app/levels/page.tsx

@@ -253,7 +253,7 @@ export default function LevelsPage() {
                         : 'amber.500',
                 rounded: 'xl',
                 p: { base: '6', md: '8' },
-                height: { base: 'auto', md: '700px' },
+                height: { base: 'auto', md: '900px' },
                 display: 'flex',
                 flexDirection: 'column',
               })}