fix: reduce playlist creation wait time after Spotify import

Cap Navidrome scan poll from 3 min to 60s, shrink post-scan buffer from 5s to 3s, and error fallback from 30s to 20s — playlist now appears sooner after downloads complete.

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

src/ui.js

@@ -357,14 +357,14 @@ async function _pollAndCreatePlaylist(jobId, tracks, playlistName) {
     await api('startScan', '');
     toast('🔍 Navidrome scannt Bibliothek…');
     await new Promise(r => setTimeout(r, 3000));
-    for (let i = 0; i < 90; i++) {
+    for (let i = 0; i < 30; i++) {
       await new Promise(r => setTimeout(r, 2000));
       const st = await api('getScanStatus', '');
       if (!st?.scanStatus?.scanning) break;
     }
-    await new Promise(r => setTimeout(r, 5000));
+    await new Promise(r => setTimeout(r, 3000));
   } catch {
-    await new Promise(r => setTimeout(r, 30000));
+    await new Promise(r => setTimeout(r, 20000));
   }
 
   await _createNdPlaylist(tracks, playlistName);