make entire product card image area clickable

The stretched-link::after overlay (z-index: 0) was blocked by
product-card-image-wrap (z-index: 1), so only the title text was
actually clickable. Wrapping the image area in a <.link> component
directly fixes this — taps/clicks bubble up to the link naturally,
and touch-scroll on the image carousel still works on mobile.

Also corrects the mode check: ThemeHook sets mode: :shop on shop pages,
not :live, so the condition is now mode != :preview (consistent with
how the title link already worked).

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

assets/css/shop/components.css

@@ -50,6 +50,7 @@
   }
 
   .product-card-image-wrap {
+    display: block;
     z-index: 1;
     overflow: hidden;
     position: relative;