fix(navigation): simplify responsive grid to 2 cols until lg breakpoint

Remove awkward 3 and 4 column layouts at sm/md breakpoints.
Now maintains clean 2-column vertical layout until 1024px,
then switches to 5-column horizontal layout.

This eliminates layout shifts in the 930-1023px range that
were affecting the bottom bar positioning.

ui/desktop/src/components/Layout/TopNavigation.tsx

@@ -469,7 +469,7 @@ export const TopNavigation: React.FC<TopNavigationProps> = ({ isExpanded, setIsE
               }}
               className="pb-0.5 overflow-y-auto lg:max-h-[2000px] md:max-h-[calc(100vh-60px)] max-h-screen"
             >
-              <div className="grid grid-cols-2 sm:grid-cols-3 md:grid-cols-4 lg:grid-cols-5 xl:grid-cols-5 gap-0.5">
+              <div className="grid grid-cols-2 sm:grid-cols-2 md:grid-cols-2 lg:grid-cols-5 xl:grid-cols-5 gap-0.5">
             {navItems.map((item, index) => {
               const isPulsing = pulsingItems.has(item.id);
               const isDragging = draggedItem === item.id;