fix(levels): improve slider tick spacing to use full width

Remove horizontal padding (90px) from tick marks container to allow emoji
tick marks to spread across the full width of the slider. This provides
better visual distribution of level indicators.

Changes:
- Change px from '90px' to '0' on tick marks container
- Tick marks now use space-between across full slider width

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

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

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

@@ -387,7 +387,7 @@ export default function LevelsPage() {
                       display: 'flex',
                       alignItems: 'center',
                       pointerEvents: 'none',
-                      px: '90px', // Half of bead width (180px / 2)
+                      px: '0', // Use full width for tick spacing
                     })}
                   >
                     <div