fix: increase z-index of pointer lock prompt overlay

Increase z-index from 1000 to 10000 to ensure the overlay
appears above all other content.

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

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

apps/web/src/arcade-games/know-your-world/components/PlayingPhase.tsx

@@ -146,7 +146,7 @@ export function PlayingPhase() {
             border: '3px solid',
             borderColor: 'blue.500',
             boxShadow: '0 10px 40px rgba(0, 0, 0, 0.5)',
-            zIndex: 1000,
+            zIndex: 10000,
             textAlign: 'center',
             cursor: 'pointer',
             transition: 'all 0.2s',