Add a header ad component to various pages across the platform

Introduce a new `HeaderAd` component for displaying AdSense ads on multiple pages, including `FolxStadlPage`, `GeschichteLiedPage`, `GipfelstammtischPage`, `Impressum`, `LivePage`, `PrivacyPolicy`, `TermsOfService`, `VideoPage`, `admin`, `home`, and `not-found`. This component is implemented in `client/src/components/HeaderAd.tsx` and integrated into the respective page components.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 45a1dcfc-f8a2-475a-a6b9-96fbb841dc27
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/60d372ff-2c10-46c7-b01b-10c3435136b0/45a1dcfc-f8a2-475a-a6b9-96fbb841dc27/HUI2eAX

client/src/pages/FolxStadlPage.tsx

@@ -9,6 +9,7 @@ import type { Video } from '@shared/schema';
 import { Input } from '@/components/ui/input';
 import { Search } from 'lucide-react';
 import AdSenseAd from '@/components/adsense-ad';
+import HeaderAd from '@/components/HeaderAd';
 
 export default function FolxStadlPage() {
   const [selectedVideo, setSelectedVideo] = useState<Video | null>(null);
@@ -232,6 +233,9 @@ export default function FolxStadlPage() {
         )}
       </div>
 
+      {/* Fixed Header Ad */}
+      <HeaderAd />
+
       {/* Main Content */}
       <div 
         className="container pt-8 pb-8"