fix(card-sorting): use blue gradient matching other game cards

Change card sorting game to use the same blue gradient as Memory Lightning
and Speed Complement Race to ensure consistent appearance on game chooser.

Updated to: linear-gradient(135deg, #dbeafe, #bfdbfe) (blue-100 to blue-200)

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

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

apps/web/src/arcade-games/card-sorting/index.ts

@@ -24,9 +24,9 @@ const manifest: GameManifest = {
   maxPlayers: 1, // Single player only
   difficulty: 'Intermediate',
   chips: ['🧠 Pattern Recognition', '🎯 Solo Challenge', '📊 Smart Scoring'],
-  color: 'teal',
-  gradient: 'linear-gradient(135deg, #ccfbf1, #99f6e4)',
-  borderColor: 'teal.200',
+  color: 'blue',
+  gradient: 'linear-gradient(135deg, #dbeafe, #bfdbfe)',
+  borderColor: 'blue.200',
   available: true,
 }