Optimize images and improve social media sharing previews

Convert images to JPG for optimization and ensure correct Open Graph tags are used for social media sharing.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 1f7e7e89-a520-4970-9645-37daadc466dc
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Event-Id: 30e90049-0ceb-4261-a159-b687b34f680b
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/f209e72a-0939-48fa-84fc-57854de71967/1f7e7e89-a520-4970-9645-37daadc466dc/s81zXmM
Replit-Helium-Checkpoint-Created: true

client/src/pages/article.tsx

@@ -73,7 +73,7 @@ function RelatedArticles({ currentSlug }: { currentSlug: string }) {
             <div className="group cursor-pointer" data-testid={`card-related-${article.id}`}>
               <div className="relative overflow-hidden rounded-md mb-3">
                 <img
-                  src={article.coverImage ? article.coverImage.replace(".webp", "-thumb.webp") : "/images/article-1.png"}
+                  src={article.coverImage ? article.coverImage.replace(".webp", "-thumb.webp") : "/images/article-1.jpg"}
                   alt={article.title}
                   className="w-full aspect-video object-cover transition-transform duration-500 group-hover:scale-105"
                   style={{ objectPosition: "center 25%" }}