Add cascading filters for Explore mode

When a product is selected, hubs and suppliers are filtered
to show only those that are relevant to that product.

app/composables/useCatalogSuppliers.ts

@@ -1,4 +1,5 @@
 import { GetSupplierProfilesDocument } from '~/composables/graphql/public/exchange-generated'
+import { GetSuppliersForProductDocument } from '~/composables/graphql/public/geo-generated'
 
 const PAGE_SIZE = 24
 
@@ -8,6 +9,7 @@ const total = ref(0)
 const isLoading = ref(false)
 const isLoadingMore = ref(false)
 const isInitialized = ref(false)
+const filterProductUuid = ref<string | null>(null)
 
 export function useCatalogSuppliers() {
   const { execute } = useGraphQL()
@@ -21,6 +23,35 @@ export function useCatalogSuppliers() {
   const fetchPage = async (offset: number, replace = false) => {
     if (replace) isLoading.value = true
     try {
+      // If filtering by product, use specialized query
+      if (filterProductUuid.value) {
+        const data = await execute(
+          GetSuppliersForProductDocument,
+          { productUuid: filterProductUuid.value },
+          'public',
+          'geo'
+        )
+        const supplierUuids = (data?.suppliersForProduct || []).map(s => s?.uuid).filter(Boolean)
+        // Fetch full profiles for these suppliers
+        if (supplierUuids.length > 0) {
+          const profilesData = await execute(
+            GetSupplierProfilesDocument,
+            { limit: supplierUuids.length, offset: 0 },
+            'public',
+            'exchange'
+          )
+          // Filter to only include suppliers that match the product filter
+          const allProfiles = profilesData?.getSupplierProfiles || []
+          items.value = allProfiles.filter(p => supplierUuids.includes(p.uuid))
+        } else {
+          items.value = []
+        }
+        total.value = items.value.length
+        isInitialized.value = true
+        return
+      }
+
+      // Default: fetch all suppliers
       const data = await execute(
         GetSupplierProfilesDocument,
         { limit: PAGE_SIZE, offset },
@@ -53,6 +84,13 @@ export function useCatalogSuppliers() {
     }
   }
 
+  const setProductFilter = (uuid: string | null) => {
+    filterProductUuid.value = uuid
+    if (isInitialized.value) {
+      fetchPage(0, true)
+    }
+  }
+
   return {
     items,
     total,
@@ -62,6 +100,7 @@ export function useCatalogSuppliers() {
     canLoadMore,
     fetchPage,
     loadMore,
-    init
+    init,
+    setProductFilter
   }
 }