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/bestellbestaetigung/components/BestellbestaetigungContent.tsx

@@ -249,7 +249,7 @@ export function BestellbestaetigungContent() {
           identical height regardless of how many lines the quote wraps
           to (a min-height alone lets whichever column has more content
           stretch the row past what the other side visually fills). */}
-      <Reveal className="relative w-full flex items-stretch h-[20rem] md:h-[24rem] bg-bg-muted overflow-hidden">
+      <Reveal className="relative w-full flex items-stretch h-[14rem] md:h-[16rem] bg-bg-muted overflow-hidden">
         <div className="relative w-full md:w-[45%] shrink-0">
           {/* -inset-1, not inset-0 — this section fades in via Reveal's
               y:28→0 transform; a plain inset-0 image can leave a