Add two new ad formats to blog articles for increased revenue

Integrates an interstitial overlay ad and a parallax ad into article pages to display advertisements.

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replit.md

@@ -28,6 +28,8 @@ The official website for Folx Music Television (folx.tv). Dark-themed bento grid
 - Recipe widget + full /rezepte subpage (21 recipes across 5 regions: Österreich, Bayern, Schwaben/Baden, Südtirol/Alpen, Norddeutschland) with AI-generated images
 - Google News RSS widget (Volksmusik/Schlager news, 5 items, auto-rotate)
 - Google AdSense integration (ca-pub-4465464714854276)
+- Interstitial overlay ad on article pages (3s delay, shows every other article visit, sessionStorage counter)
+- Parallax/reveal ad below article content (sticky background ad revealed on scroll)
 - Web Push Notifications (bell icon in header, auto-send on new articles, admin panel at /admin/push)
 - Article listing with featured carousel and category filtering
 - HTML content supports embedded iframes (bunny.net, YouTube, Facebook, Instagram, TikTok)