Improve video loading and display with error handling and updated headers

Improves thumbnail loading in VideoCard component with error handling and updates response headers in /thumbnail route.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 50814a1e-92e4-4968-856f-7bc7eedf5e8f
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/8cc42625-c1f5-4e43-99bd-77f2c4dedee2/50814a1e-92e4-4968-856f-7bc7eedf5e8f/WNLqOHv

server/routes.ts

@@ -167,8 +167,9 @@ export async function registerRoutes(app: Express): Promise<Server> {
         </svg>
       `;
       
-      res.setHeader('Content-Type', 'image/svg+xml');
+      res.setHeader('Content-Type', 'image/svg+xml; charset=utf-8');
       res.setHeader('Cache-Control', 'public, max-age=86400');
+      res.setHeader('Access-Control-Allow-Origin', '*');
       res.send(svg);
       
     } catch (error) {