Add used-product flag for store listings.

Merchants can mark items as used on create/edit, see a used badge on cards, and filter the store list for used products.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/business/src/components/StoreItemCard.tsx

@@ -115,6 +115,9 @@ export function StoreItemCard({
           {listing.showFestival && (
             <span className={styles.festivalBadge}>{t('storeItems.card.festival')}</span>
           )}
+          {listing.isUsed && (
+            <span className={styles.usedBadge}>{t('storeItems.card.used')}</span>
+          )}
           {listing.productTotalStock > 0 && (
             <span className={styles.stockBadge}>
               {t('storeItems.card.inStock', { count: listing.productTotalStock })}