feat(seller-tiles): remove seller name overlay on desktop grid

The homepage seller tiles now show just the shop image on all breakpoints.
The desktop-only bottom gradient + name label was making some brand images
harder to read; the shop click target is unchanged and username is still
available on hover-tap navigation to /seller/<username>.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/components/SellerTilesGrid.tsx

@@ -68,17 +68,6 @@ const SellerTilesGrid = ({
               </div>
             )}
 
-            {/* Desktop-only name overlay (matches the desktop design) */}
-            {seller.sellerName ? (
-              <>
-                <div className="hidden lg:block absolute inset-0 bg-gradient-to-t from-black/60 to-transparent" />
-                <div className="hidden lg:flex absolute inset-x-0 bottom-0 p-4 items-end">
-                  <span className="text-white font-bold text-[15px] truncate">
-                    {seller.sellerName}
-                  </span>
-                </div>
-              </>
-            ) : null}
           </Link>
         ))}
       </div>