Implement unified catalog search with token-based filtering

- Add useCatalogSearch composable for managing unified search state
- Add UnifiedSearchBar component with token chips for filters
- Add CatalogHero component for empty/landing state
- Create grid components for each display mode:
  - CatalogGridProducts, CatalogGridSuppliers, CatalogGridHubs
  - CatalogGridHubsForProduct, CatalogGridProductsFromSupplier
  - CatalogGridProductsInHub, CatalogGridOffers
- Add unified catalog page at /catalog with query params
- Remove SubNavigation from catalog section (kept for other sections)
- Update all links to use new unified catalog paths
- Delete old nested catalog pages (offers/suppliers/hubs flows)
- Add i18n translations for catalog section

app/pages/catalog/hubs/[id]/index.vue

@@ -78,7 +78,7 @@ const navigationFilters = computed(() => {
 // Handle removing navigation filter (navigate back)
 const handleRemoveFilter = (filterId: string) => {
   if (filterId === 'hub') {
-    navigateTo(localePath('/catalog/hubs'))
+    navigateTo(localePath('/catalog?select=hub'))
   }
 }
 
@@ -105,9 +105,9 @@ const mapItems = computed(() => {
   }]
 })
 
-// Navigate to product page
+// Navigate to unified catalog with hub + product = offers
 const goToProduct = (productId: string) => {
-  navigateTo(localePath(`/catalog/hubs/${hubId.value}/${productId}`))
+  navigateTo(localePath(`/catalog?hub=${hubId.value}&product=${productId}`))
 }
 
 // Mock price history generator (seeded by uuid for consistent results)