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/components/catalog/OffersBreadcrumbs.vue

@@ -25,17 +25,17 @@ const { t } = useI18n()
 const breadcrumbs = computed(() => {
   const crumbs: Array<{ label: string; to?: string }> = []
 
-  // Products list
+  // Catalog root
   crumbs.push({
     label: t('breadcrumbs.products', 'Products'),
-    to: localePath('/catalog/offers')
+    to: localePath('/catalog?select=product')
   })
 
   // Product
   if (props.productId) {
     crumbs.push({
       label: props.productName || `#${props.productId.slice(0, 8)}...`,
-      to: props.hubId ? localePath(`/catalog/offers/${props.productId}`) : undefined
+      to: props.hubId ? localePath(`/catalog?product=${props.productId}`) : undefined
     })
   }