Desktop fixes: product seller + actions, collection cover, masonry skeleton

- product: show seller (logo + name) in the desktop info column (was missing
  after hiding the mobile header); action icons (save/share/collection/AI) are
  now circular bordered buttons on desktop instead of a bare icon row
- collection detail: cover constrained to a 360px portrait column with
  object-cover (fixes over-long image + side margins); tighter spacing
- masonry: only render the loading skeleton while actively fetching (removes
  the persistent grey block before the footer); sentinel moved above it

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/components/MondrianProductList.tsx

@@ -194,8 +194,8 @@ const MondrianProductList = ({
                 ))}
               </div>
 
-              {hasNextPage && <MondrianSkeleton isMini={true} />}
               <div ref={loadMoreRef} className="h-px w-full" />
+              {isFetchingNextPage && <MondrianSkeleton isMini={true} />}
             </>
           )}
         </>

app/components/product/ProductActions.tsx

@@ -160,53 +160,58 @@ export const ProductActions = ({ productId }: { productId: string }) => {
     }
   };
 
+  const actionBtn =
+    "flex items-center justify-center cursor-pointer transition-colors lg:w-10 lg:h-10 lg:rounded-full lg:border lg:border-WHITE3 lg:hover:bg-WHITE2";
+
   return (
     <>
-      <div className="flex w-full mt-4 px-4 justify-between">
-        <div className="flex gap-8">
-          {isCheckingBookmark ? (
-            <Skeleton className="h-6 w-6 rounded-full" />
-          ) : isBookmarked ? (
-            <>
-              {isDeletingBookmark ? (
+      <div className="flex w-full mt-4 px-4 justify-between lg:mt-0 lg:px-0">
+        <div className="flex gap-8 lg:gap-2.5">
+          <button
+            type="button"
+            onClick={handleBookmark}
+            aria-label="ذخیره"
+            className={actionBtn}
+          >
+            {isCheckingBookmark ? (
+              <Skeleton className="h-6 w-6 rounded-full" />
+            ) : isBookmarked ? (
+              isDeletingBookmark ? (
                 <Loader2 className="h-5 w-5 animate-spin" />
               ) : (
-                <Bookmark
-                  size={20}
-                  className="text-PRIMARY fill-current cursor-pointer"
-                  onClick={handleBookmark}
-                />
-              )}
-            </>
-          ) : (
-            <>
-              {isBookmarking ? (
-                <Loader2 className="h-5 w-5 animate-spin" />
-              ) : (
-                <BookmarkMinus
-                  size={20}
-                  className="cursor-pointer"
-                  onClick={handleBookmark}
-                />
-              )}
-            </>
-          )}
-          <Share2
-            size={20}
-            className="cursor-pointer"
+                <Bookmark size={20} className="text-PRIMARY fill-current" />
+              )
+            ) : isBookmarking ? (
+              <Loader2 className="h-5 w-5 animate-spin" />
+            ) : (
+              <BookmarkMinus size={20} />
+            )}
+          </button>
+          <button
+            type="button"
             onClick={() => setIsShareDrawerOpen(true)}
-          />
-          <Layers
-            size={20}
-            className="cursor-pointer"
+            aria-label="اشتراک‌گذاری"
+            className={actionBtn}
+          >
+            <Share2 size={20} />
+          </button>
+          <button
+            type="button"
             onClick={handleAddToSet}
-          />
+            aria-label="افزودن به ست"
+            className={actionBtn}
+          >
+            <Layers size={20} />
+          </button>
           <div className="relative">
-            <Sparkles
-              size={20}
-              className="cursor-pointer animate-pulse text-PRIMARY"
+            <button
+              type="button"
               onClick={handleOpenAIModal}
-            />
+              aria-label="پرو با هوش مصنوعی"
+              className={actionBtn}
+            >
+              <Sparkles size={20} className="animate-pulse text-PRIMARY" />
+            </button>
             {showAIFeatureTooltip && (
               <div className="absolute bottom-full right-0 mb-2 z-50 animate-bounce">
                 <div className="relative bg-gradient-to-r from-purple-600 to-pink-500 text-WHITE px-3 py-2 rounded-lg shadow-xl whitespace-nowrap border border-white/20">

app/components/product/ProductDetailView.tsx

@@ -16,6 +16,7 @@ import { Button } from "../ui/button";
 import { useNavigate, Link } from "@remix-run/react";
 import { useSimilarProductsInfinite } from "~/requestHandler/use-product-hooks";
 import MondrianProductList from "../MondrianProductList";
+import SellerLogo from "../SellerLogo";
 
 interface ProductDetailViewProps {
   product: ProductDetailType;
@@ -243,6 +244,22 @@ export const ProductDetailView = memo(function ProductDetailView({
 
         {/* Info */}
         <div className="flex flex-col">
+          {/* Seller (desktop) */}
+          {!isOwner && product.seller?.username ? (
+            <Link
+              to={`/seller/${product.seller.username}`}
+              className="hidden lg:flex items-center gap-2.5 mb-1"
+            >
+              <SellerLogo
+                size="sm"
+                src={product.seller?.storeLogo}
+                alt="seller"
+              />
+              <span className="font-bold text-[15px]">
+                {product.seller.username}
+              </span>
+            </Link>
+          ) : null}
           {/* Inactive Product Status */}
           {!productActiveStatus && isOwner ? (
             <div className="flex gap-1 px-4 w-full justify-between items-center mt-2 lg:px-0">

app/routes/collection.$id.tsx

@@ -141,14 +141,14 @@ export default function CollectionDetail() {
       {/* Content */}
       <div className="flex flex-col lg:max-w-[1320px] lg:mx-auto lg:w-full lg:px-8 lg:pt-6">
         {/* Collection Header */}
-        <div className="flex flex-col gap-4 p-4 border-b border-inner-border lg:grid lg:grid-cols-[1.3fr_1fr] lg:gap-8 lg:items-center lg:p-0 lg:py-8 lg:border-0">
+        <div className="flex flex-col gap-4 p-4 border-b border-inner-border lg:grid lg:grid-cols-[360px_1fr] lg:gap-8 lg:items-start lg:p-0 lg:py-6 lg:border-0">
           {/* Cover Image */}
-          <div className="relative overflow-hidden rounded-xl w-full mx-auto h-[65vh] bg-gray-100 lg:h-auto lg:aspect-[3/4] lg:bg-WHITE2">
+          <div className="relative overflow-hidden rounded-xl w-full mx-auto h-[65vh] bg-gray-100 lg:h-auto lg:aspect-[3/4]">
             {collection.coverImageUrl ? (
               <img
                 src={collection.coverImageUrl}
                 alt={collection.title || "Collection"}
-                className="w-full h-full object-cover lg:object-contain"
+                className="w-full h-full object-cover"
               />
             ) : (
               <div className="w-full h-full flex items-center justify-center bg-WHITE2">