fix(404): match /bestellbestaetigung's testimonial-band fixes, shrink band height

Same fixed-height + -inset-1 treatment as page-bestellbestaetigung's
own testimonial band, and the same class of top-edge boundary
artifact turned up in 404-testimonial-photo.jpg too (invisible in a
downscaled preview, visible once object-cover scales it up in the
browser) — re-cropped 15px further down to clear it.

Also shrunk both pages' testimonial band from h-[20rem]/24rem to
h-[14rem]/16rem — the taller version left too much empty vertical
space around the 3-line quote.

feat(cart): show the -XX% sale badge on cart line-item photos too

Same badge already used in the shop grid/spotlight/todo-cards
pricing panel, now also on /cart's product thumbnails when that
item has a compareAtPrice set.

app/cart/components/CartContent.tsx

@@ -104,6 +104,11 @@ export function CartContent({
                 <div className="flex flex-col sm:flex-row gap-4 sm:gap-6 items-start sm:items-center w-full">
                   <div className="relative size-[9.375rem] shrink-0 rounded-sm overflow-hidden">
                     <Image src={product.image} alt={product.name} fill sizes="150px" className="object-cover" />
+                    {discount !== null && (
+                      <span className="absolute top-2 left-2 rounded-full bg-brand px-2 py-0.5 text-label font-bold text-text-primary">
+                        -{discount}%
+                      </span>
+                    )}
                   </div>
                   <div className="flex flex-col gap-[0.625rem] items-start flex-1 min-w-0 w-full">
                     <p