Watch Together: Embed-Fehlerbehandlung, klickbare Queue, Video-Titel

- YouTube onError Handler: Erkennt Error 101/150 (Embedding deaktiviert),
  zeigt Fehlermeldung + "Auf YouTube oeffnen" Link, auto-skip nach 3s
- Queue-Items klickbar fuer Host (play_video mit Index)
- Video-Titel werden via noembed.com oEmbed API geholt
- Server-Endpoint: GET /api/watch-together/video-info?url=...
- "Hinzufuegen" Button zeigt Ladezustand waehrend Titel-Fetch

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/plugins/watch-together/index.ts

@@ -470,6 +470,27 @@ const watchTogetherPlugin: Plugin = {
       res.json({ rooms: getRoomList() });
     });
 
+    // Fetch video title via noembed.com (CORS-friendly oEmbed proxy)
+    app.get('/api/watch-together/video-info', async (req, res) => {
+      const url = String(req.query.url || '');
+      if (!url) {
+        res.json({ title: '' });
+        return;
+      }
+      try {
+        const response = await fetch(`https://noembed.com/embed?url=${encodeURIComponent(url)}`);
+        if (response.ok) {
+          const data = await response.json() as Record<string, any>;
+          if (data.title) {
+            res.json({ title: data.title, provider: data.provider_name || '' });
+            return;
+          }
+        }
+      } catch { /* ignore fetch errors */ }
+      // Fallback: return empty title (frontend will use URL)
+      res.json({ title: '' });
+    });
+
     // Beacon cleanup endpoint — called via navigator.sendBeacon() on page unload
     app.post('/api/watch-together/disconnect', (req, res) => {
       let body = '';