about: add Header/Footer to /about/contact + /about/advertise; banners on all three

/about/contact and /about/advertise were rendering bare <main> tags
with no site chrome at all — no header, no footer, no banners. Both
are now wrapped with the standard
  <div className="min-h-screen bg-background"><Header />…<Footer /></div>
shell that the rest of the site uses, which auto-brings the site-wide
728x90 leaderboard with it.

/about/team already had Header+Footer but no in-content banner.

In addition to the header leaderboard, each of the three pages now
also renders one in-content 728x90 banner (gated on
ADS_728X90.length > 0, hidden on mobile to match the header banner's
display rules). This brings the about/* pages in line with the ad
inventory of /show-coverage and the other category landing pages.

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

src/app/about/team/page.tsx

@@ -1,6 +1,8 @@
 import { createClient } from "@supabase/supabase-js";
 import Header from "@/components/Header";
 import Footer from "@/components/Footer";
+import AdImage from "@/components/AdImage";
+import { ADS_728X90, shuffle } from "@/lib/ads";
 
 export const dynamic = "force-dynamic";
 export const revalidate = 600;
@@ -66,6 +68,13 @@ export default async function TeamPage() {
             </li>
           ))}
         </ul>
+
+        {/* In-content 728x90 banner */}
+        {ADS_728X90.length > 0 && (
+          <div className="mt-12 hidden md:flex justify-center" aria-label="Advertisement">
+            <AdImage ad={shuffle(ADS_728X90)[0]} page="team" />
+          </div>
+        )}
       </main>
       <Footer />
     </div>