✨ Major code cleanup and optimization

- Removed unnecessary dependencies (fs, path - built-in modules)
- Organized debug files into /debug folder
- Reduced excessive console logging for cleaner output
- Fixed README formatting issues
- Added comprehensive .gitignore
- Removed redundant backup files (game.js.new)
- Fixed duplicate code patterns in analytics
- Created CLEANUP_SUMMARY.md documentation
- Regenerated clean package-lock.json

No breaking changes - all functionality preserved

public/gamification.css

@@ -249,9 +249,9 @@
 /* User profile stats */
 .user-stats {
   display: grid;
-  grid-template-columns: repeat(4, 1fr);
-  gap: 1rem;
-  margin-bottom: 1.5rem;
+  grid-template-columns: repeat(auto-fit, minmax(min(200px, 100vw), 1fr));
+  gap: clamp(0.5rem, 2vw, 1.5rem);
+  margin-bottom: clamp(1rem, 2vw, 1.5rem);
 }
 
 .stat-card {