fix: add @reference directive for Tailwind 4 scoped styles

Add @reference 'tailwindcss' to components using @apply in scoped styles:
- MainNavigation.vue
- SubNavigation.vue
- GlobalSearchBar.vue

Required for Tailwind CSS 4 compatibility with scoped Vue styles.

app/components/navigation/SubNavigation.vue

@@ -52,6 +52,8 @@ const isActive = (path: string) => {
 </script>
 
 <style scoped>
+@reference "tailwindcss";
+
 .subnav-item {
   @apply px-4 py-2 rounded-full text-sm font-medium transition-colors whitespace-nowrap;
   @apply text-base-content/70 hover:text-base-content hover:bg-base-200;