Add grid layout for catalog cards + hover shadow

- CatalogPage: added gridColumns prop (1/2/3 columns)
- Card: added hover:shadow-lg on interactive cards
- Products, hubs, suppliers pages now use 3-column grid
- Offers remain full-width (gridColumns=1 default)

app/components/ui/Card.vue

@@ -35,7 +35,9 @@ const toneMap: Record<string, string> = {
 const cardClass = computed(() => {
   const paddingClass = paddingMap[props.padding] || paddingMap.medium
   const toneClass = toneMap[props.tone] || toneMap.default
-  const interactiveClass = props.interactive ? 'cursor-pointer' : ''
+  const interactiveClass = props.interactive
+    ? 'cursor-pointer hover:shadow-lg transition-shadow duration-200'
+    : ''
   const baseClass = 'card'
   return [baseClass, paddingClass, toneClass, interactiveClass].filter(Boolean).join(' ')
 })