homepage feed: remove duplicate category+date in advanced panel (kept author/source only); article page: render SidebarAdStack instead of placeholder

src/app/articles/[slug]/ArticleDetailClient.tsx

@@ -4,6 +4,7 @@ import Link from "next/link";
 import AppImage from "@/components/ui/AppImage";
 import Header from "@/components/Header";
 import Footer from "@/components/Footer";
+import SidebarAdStack from "@/components/SidebarAdStack";
 import { createClient } from "@/lib/supabase/client";
 import type { Article } from "@/lib/articles/types";
 
@@ -436,13 +437,8 @@ export default function ArticleDetailClient({ article, relatedArticles }: Articl
               </Link>
             </div>
 
-            {/* Ad placeholder */}
-            <div className="ad-placeholder w-full h-[250px] flex items-center justify-center">
-              <div className="text-center">
-                <p className="text-[#444] text-xs font-body">Advertisement</p>
-                <p className="text-[#333] text-[10px] font-body mt-1">300×250</p>
-              </div>
-            </div>
+            {/* Sidebar ad stack — 300x600 + 300x250 rotating */}
+            <SidebarAdStack />
           </aside>
         </div>
       </article>