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/navigation/MainNavigation.vue

@@ -177,7 +177,7 @@ const { t } = useI18n()
 
 const tabs = computed(() => [
   { key: 'search', label: t('cabinetNav.search'), path: '/', auth: false },
-  { key: 'catalog', label: t('cabinetNav.catalog'), path: '/catalog/offers', auth: false },
+  { key: 'catalog', label: t('cabinetNav.catalog'), path: '/catalog', auth: false },
   { key: 'orders', label: t('cabinetNav.orders'), path: '/clientarea/orders', auth: true },
   { key: 'seller', label: t('cabinetNav.seller'), path: '/clientarea/offers', auth: true, seller: true },
 ])