ads: float SidebarAdStack at top of <main> on 7 more pages

gear, technology, search, reading-list, show-coverage, authors/[slug],
forum/thread/[id] all now render the 300x600 + 300x250 stack as a
floating right column at the top of the content area. Existing
single-column page structure preserved (content wraps).

Maximizes impression count: every pageview across these pages now
counts 300x600 + every 300x250 in the stack, on top of the existing
728x90 in Header.

src/app/search/page.tsx

@@ -6,6 +6,7 @@ import AppImage from "@/components/ui/AppImage";
 import AdImage from "@/components/AdImage";
 import { ADS_728X90, shuffle } from "@/lib/ads";
 import { searchLegacyArticles } from "@/lib/articles/legacy-source";
+import SidebarAdStack from "@/components/SidebarAdStack";
 
 export const revalidate = 60;
 
@@ -46,6 +47,7 @@ export default async function SearchPage({ searchParams }: SearchPageProps) {
       </div>
 
       <main className="max-w-container mx-auto px-4 py-8">
+      <aside className="float-right ml-6 mb-6 hidden lg:block max-w-[300px]"><SidebarAdStack /></aside>
         {query && results.length === 0 && (
           <div className="py-16 text-center">
             <p className="text-[#555] font-body text-sm mb-3">No articles match your search.</p>