ui(cards): object-contain on article-card images so portraits don't crop

Boxes stay sized; tall/odd-ratio images letterbox cleanly against the
existing slate card background instead of being chopped at the edges.
Applied to FeaturedBento, FeaturedBentoFromDb, ArticleFeed, NewsPageClient,
SpotlightCarousel, FeaturedCarousel, AISuggestedArticles, search/page.tsx.

Avatars (rounded-full) unchanged — still object-cover.

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

src/components/FeaturedBentoFromDb.tsx

@@ -95,7 +95,7 @@ export default async function FeaturedBento() {
               <img
                 src={img(hero)}
                 alt={hero.featured_image_alt || hero.title}
-                className="w-full h-full object-cover"
+                className="w-full h-full object-contain"
               />
               <div className="absolute inset-0 bg-gradient-to-t from-black via-black/65 to-transparent" />
 
@@ -146,7 +146,7 @@ export default async function FeaturedBento() {
                   <img
                     src={img(r)}
                     alt={r.featured_image_alt || r.title}
-                    className="w-full h-full object-cover"
+                    className="w-full h-full object-contain"
                   />
                 </div>
                 <div className="p-3 flex flex-col gap-1 flex-1 min-h-0 overflow-hidden">