Add wishlist button to cart page's related-products cards

RelatedProducts.tsx was the only product-card grid missing the
WishlistButton (ProductGrid.tsx/ProductSpotlight.tsx already had it).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/cart/components/RelatedProducts.tsx

@@ -7,6 +7,7 @@ import { formatPrice, discountPercent } from "../../lib/format";
 import { effectiveTaxRate } from "../../lib/cartTotals";
 import { Reveal } from "../../components/Reveal";
 import { AddToCartInlineButton, FEEDBACK_MS } from "../../components/AddToCartInlineButton";
+import { WishlistButton } from "../../components/WishlistButton";
 import { useCart } from "../../lib/cart";
 
 const DISPLAY_COUNT = 3;
@@ -30,7 +31,15 @@ function pickAvailable(allIds: string[], excludeIds: string[], keep: string[], c
   return [...keep, ...pickRandom(allIds, [...excludeIds, ...keep], missing)];
 }
 
-export function RelatedProducts({ defaultTaxRate, kleinunternehmer }: { defaultTaxRate: number; kleinunternehmer: boolean }) {
+export function RelatedProducts({
+  defaultTaxRate,
+  kleinunternehmer,
+  wishlistEnabled,
+}: {
+  defaultTaxRate: number;
+  kleinunternehmer: boolean;
+  wishlistEnabled: boolean;
+}) {
   const cart = useCart();
   const products = useProducts();
   // Cart/checkout resolve any product regardless of `active` (see
@@ -175,6 +184,9 @@ export function RelatedProducts({ defaultTaxRate, kleinunternehmer }: { defaultT
                   </span>
                 )
               )}
+              {wishlistEnabled && (
+                <WishlistButton productId={product.numericId} className="absolute top-3 right-3" revealOnHover />
+              )}
             </div>
             <div className="flex flex-col gap-4 items-start px-5 pb-5 pt-2 w-full flex-1">
               <div className="flex flex-col gap-1 items-start w-full">