Speed up timeline load with portrait thumbs, bootstrap API, and caching.

Add catalog bootstrap endpoint, portrait thumbnail pipeline, lazy queued timeline images, gzip compression, and 3D texture throttling with code-split VirtualGallery.

client/src/components/PaintingDetail.tsx

@@ -130,6 +130,8 @@ function InfluenceCard({
           <img
             src={imageUrl(inf.artist_portrait)}
             alt={artistName}
+            loading="lazy"
+            decoding="async"
             onError={(e) => {
               (e.target as HTMLImageElement).src = '/placeholder-portrait.svg';
             }}
@@ -164,6 +166,8 @@ function InfluenceCard({
         <img
           src={paintingImageUrl({ id: inf.id, image_path: inf.image_path }) ?? '/placeholder-art.svg'}
           alt={inf.title || 'Painting'}
+          loading="lazy"
+          decoding="async"
           onError={(e) => {
             (e.target as HTMLImageElement).src = '/placeholder-art.svg';
           }}