Introduce a new custom loading spinner component with animations

Replace existing simple loading indicators with a new animated `LoadingSpinner` component across various pages and components, including `HLSPreviewThumbnail`, `NetflixGrid`, `ThumbnailGenerator`, `VideoAds`, `VideoGrid`, `FolxStadlPage`, `GeschichteLiedPage`, `GipfelstammtischPage`, and `VideoPage`. The new component features a customizable size, text, and a pulsing gradient animation, improving the visual feedback during loading states.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 890577b1-c154-40a4-a177-a0c6d55320c3
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/8cc42625-c1f5-4e43-99bd-77f2c4dedee2/890577b1-c154-40a4-a177-a0c6d55320c3/UbX8tN8

client/src/pages/FolxStadlPage.tsx

@@ -78,7 +78,13 @@ export default function FolxStadlPage() {
   if (isLoading) {
     return (
       <div className="min-h-screen bg-bunny-dark flex items-center justify-center">
-        <div className="text-white text-xl">Wird geladen...</div>
+        <div className="text-center">
+          <div className="w-16 h-16 gradient-primary rounded-lg flex items-center justify-center shadow-lg animate-pulse mb-4 mx-auto">
+            <div className="w-0 h-0 border-l-[12px] border-l-white border-y-[9px] border-y-transparent ml-1"></div>
+          </div>
+          <h3 className="text-white text-xl font-bold mb-2">go4.video</h3>
+          <p className="text-bunny-light">Loading FOLX STADL...</p>
+        </div>
       </div>
     );
   }