Add a mobile-specific sticky ad banner at the bottom of the screen

Introduces a new `MobileStickyAd` component that displays a 320x50px ad banner at the bottom of the screen on mobile devices only. The ad appears after a 2-second delay and can be dismissed by the user for the session. The footer dynamically adjusts its padding to prevent content overlap with the sticky ad. The `replit.md` file is updated to reflect this new feature.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 23852c00-4779-460a-9e0c-d09fee4b6c92
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Event-Id: db8604a4-d491-44c8-b0ac-b67d779b436a
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/f209e72a-0939-48fa-84fc-57854de71967/23852c00-4779-460a-9e0c-d09fee4b6c92/tdiozLO
Replit-Helium-Checkpoint-Created: true

client/src/components/footer.tsx

@@ -1,5 +1,6 @@
 import { Link } from "wouter";
 import { SiFacebook, SiInstagram, SiYoutube, SiTiktok } from "react-icons/si";
+import { useIsMobile } from "@/hooks/use-mobile";
 
 const SOCIAL_LINKS = [
   { href: "https://www.facebook.com/folxtv/", icon: SiFacebook, label: "Facebook", testId: "link-social-facebook" },
@@ -8,7 +9,13 @@ const SOCIAL_LINKS = [
   { href: "https://www.tiktok.com/@folxtv", icon: SiTiktok, label: "TikTok", testId: "link-social-tiktok" },
 ];
 
+const STICKY_AD_DISMISS_KEY = "folx-sticky-ad-dismissed";
+
 export default function Footer({ narrow }: { narrow?: boolean }) {
+  const isMobile = useIsMobile();
+  const stickyAdDismissed = typeof window !== "undefined" && sessionStorage.getItem(STICKY_AD_DISMISS_KEY);
+  const showStickyPadding = isMobile && !stickyAdDismissed;
+
   return (
     <footer className="border-t border-border mt-10" data-testid="footer">
       <div className={`${narrow ? "max-w-4xl" : "max-w-7xl"} mx-auto px-4 sm:px-6 lg:px-8 py-8 relative z-20`}>
@@ -113,6 +120,7 @@ export default function Footer({ narrow }: { narrow?: boolean }) {
           </p>
         </div>
       </div>
+      {showStickyPadding && <div className="h-20" aria-hidden="true" />}
     </footer>
   );
 }