Fix guest-cart TypeScript so production Next builds succeed.

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

src/lib/guest-cart.ts

@@ -36,20 +36,20 @@ function parseItems(raw: string | null): CartItem[] {
 
 /** Map storefront cart lines to the shared guest-cart shape (id = variant id). */
 export function toMeshkeeGuestItems(items: CartItem[]): MeshkeeGuestCartItem[] {
-  return items
-    .map((item) => {
-      const variantId = (item.storeItemVariantId || item.id || "").trim();
-      if (!variantId) return null;
-      return {
-        id: variantId,
-        name: item.name || "محصول",
-        slug: item.slug || undefined,
-        price: item.price,
-        image: item.image ?? null,
-        quantity: Math.max(1, Math.floor(item.quantity) || 1),
-      };
-    })
-    .filter((item): item is MeshkeeGuestCartItem => item != null);
+  const result: MeshkeeGuestCartItem[] = [];
+  for (const item of items) {
+    const variantId = (item.storeItemVariantId || item.id || "").trim();
+    if (!variantId) continue;
+    result.push({
+      id: variantId,
+      name: item.name || "محصول",
+      ...(item.slug ? { slug: item.slug } : {}),
+      price: item.price,
+      image: item.image ?? null,
+      quantity: Math.max(1, Math.floor(item.quantity) || 1),
+    });
+  }
+  return result;
 }
 
 export function encodeGuestCartForUrl(items: CartItem[]): string {