fix: remove unused graphqlUrl variable in product-banner-data route

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/api/theme/product-banner-data/route.ts

@@ -40,7 +40,6 @@ export async function GET(req: NextRequest) {
       }
     } else if (ref) {
       // Recherche par SKU via GraphQL
-      const graphqlUrl = baseUrl.replace('/admin/api/', '/admin/api/').replace('products', '').replace(/\/$/, '') + '/../graphql.json'
       const domain = process.env.SHOPIFY_STORE_DOMAIN
       const gqlRes = await fetch(`https://${domain}/admin/api/${API_VERSION}/graphql.json`, {
         method: 'POST',