Add an artist listing page and improve SEO for various pages

Introduces a new `/kuenstler` page, API endpoint `/api/artists`, and enhances meta tags on `index.html` and for crawler requests on `/kuenstler`. Adds `KuenstlerPage.tsx` and updates `routes.ts` and `index.html`.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 401e2ec0-e00d-4f10-9d0e-60f3d479f9a5
Replit-Commit-Checkpoint-Type: intermediate_checkpoint
Replit-Commit-Event-Id: 69ee4fdb-c617-4cdd-b9f6-d3fab268d533
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/60d372ff-2c10-46c7-b01b-10c3435136b0/401e2ec0-e00d-4f10-9d0e-60f3d479f9a5/qFrskyV

client/src/pages/home.tsx

@@ -56,6 +56,13 @@ export default function Home() {
     if (metaDescription) {
       metaDescription.setAttribute('content', 'Folx TV - Nummer 1 in Europa für Volksmusik und Schlager. Video Streaming Plattform mit Musik, Unterhaltung und Live-Streaming.');
     }
+    let metaKeywords = document.querySelector('meta[name="keywords"]');
+    if (!metaKeywords) {
+      metaKeywords = document.createElement('meta');
+      metaKeywords.setAttribute('name', 'keywords');
+      document.head.appendChild(metaKeywords);
+    }
+    metaKeywords.setAttribute('content', 'Volksmusik, Schlager, Folx TV, Kastelruther Spatzen, Monika Martin, Oswald Sattler, Angela Wiedl, Die Grubertaler, Michael Hirte, Sašo Avsenik, Jonny Hill, Rosanna Rocci, Linda Feller, Julia Buchner, Melanie Payer, Marlena Martinelli, Musikvideo, Streaming');
   }, []);
 
   // Update videos when new data comes in