feat(VirtualList): add auto-pagination and correct scrollbar height

- Add 'total' prop to VirtualList for accurate scrollbar height in pagination scenarios
- Add 'onNearBottom' callback to trigger auto-loading when user scrolls near end
- Update FontVirtualList to forward the new props
- Implement auto-pagination in SuggestedFonts component (remove manual Load More button)
- Display loading indicator when fetching next batch
- Show accurate font count (e.g., "Showing 150 of 1920 fonts")

Key changes:
- VirtualList now uses total count for height calculation instead of items.length
- Auto-fetches next page when user scrolls within 5 items of the end
- Only fetches if hasMore is true and not already fetching
- Backward compatible: total defaults to items.length when not provided

src/entities/Font/ui/FontVirtualList/FontVirtualList.svelte

@@ -10,9 +10,10 @@ import { appliedFontsManager } from '../../model';
 
 interface Props extends Omit<ComponentProps<typeof VirtualList<T>>, 'onVisibleItemsChange'> {
     onVisibleItemsChange?: (items: T[]) => void;
+    onNearBottom?: (lastVisibleIndex: number) => void;
 }
 
-let { items, children, onVisibleItemsChange, ...rest }: Props = $props();
+let { items, children, onVisibleItemsChange, onNearBottom, ...rest }: Props = $props();
 
 function handleInternalVisibleChange(visibleItems: T[]) {
     // Auto-register fonts with the manager
@@ -22,12 +23,18 @@ function handleInternalVisibleChange(visibleItems: T[]) {
     // Forward the call to any external listener
     onVisibleItemsChange?.(visibleItems);
 }
+
+function handleNearBottom(lastVisibleIndex: number) {
+    // Forward the call to any external listener
+    onNearBottom?.(lastVisibleIndex);
+}
 </script>
 
 <VirtualList
     {items}
     {...rest}
     onVisibleItemsChange={handleInternalVisibleChange}
+    onNearBottom={handleNearBottom}
 >
     {#snippet children(scope)}
         {@render children(scope)}