refactor(ui): reduce IconButton size by 25%

- Change default size from 44px to 33px (25% reduction)
- Update min-width and min-height in CSS to match
- Apply size reduction to toggle-sidebar-btn as well for consistency

src/components/IconButton.tsx

@@ -17,7 +17,7 @@ const IconButton: React.FC<IconButtonProps> = ({
   title,
   ariaLabel,
   variant = 'ghost',
-  size = 44
+  size = 33
 }) => {
   return (
     <button