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

i18n/locales/en/catalog.json

@@ -0,0 +1,36 @@
+{
+  "catalog": {
+    "filters": {
+      "product": "Product",
+      "supplier": "Supplier",
+      "hub": "Hub",
+      "location": "Location",
+      "quantity": "Quantity"
+    },
+    "search": {
+      "placeholder": "Find an offer...",
+      "searchProducts": "Search products...",
+      "searchSuppliers": "Search suppliers...",
+      "searchHubs": "Search hubs..."
+    },
+    "hero": {
+      "title": "Find the best offer",
+      "subtitle": "Select a product, supplier, or hub to start searching"
+    },
+    "headers": {
+      "selectProduct": "Select a product",
+      "selectSupplier": "Select a supplier",
+      "selectHub": "Select a hub",
+      "hubsForProduct": "Hubs with product",
+      "productsFromSupplier": "Supplier products",
+      "productsInHub": "Products in hub",
+      "offers": "Offers"
+    },
+    "empty": {
+      "noProducts": "No products found",
+      "noSuppliers": "No suppliers found",
+      "noHubs": "No hubs found",
+      "noOffers": "No offers found"
+    }
+  }
+}