feat: 投稿リスト一覧の作り変更（#134） (#135)

Merge branch 'main' into feature/134

#134 細部

#134

Co-authored-by: miteruzo <miteruzo@naver.com>
Reviewed-on: #135

frontend/src/components/PostList.tsx

@@ -12,15 +12,14 @@ export default (({ posts, onClick }: Props) => (
     <div className="flex flex-wrap gap-6 p-4">
       {posts.map ((post, i) => (
 	  <Link to={`/posts/${ post.id }`}
-		key={i}
+		key={post.id}
 		className="w-40 h-40 overflow-hidden rounded-lg shadow-md hover:shadow-lg"
 		onClick={onClick}>
 	    <img src={post.thumbnail || post.thumbnailBase || undefined}
 		 alt={post.title || post.url}
 		 title={post.title || post.url || undefined}
-		 loading="eager"
-		 fetchPriority="high"
+		 loading={i < 12 ? 'eager' : 'lazy'}
 		 decoding="async"
-		 className="object-none w-full h-full" />
+		 className="object-cover w-full h-full"/>
 	  </Link>))}
     </div>)) satisfies FC<Props>