fix: fail fast on Spotify 429 instead of retrying into timeout

Retrying with wait times (23s + 60s + 60s) exceeded the 120s global
timeout and showed a generic timeout error. Now returns immediately
with a RATE_LIMITED error and shows the user how long to wait.

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

src/spotify.js

@@ -68,6 +68,7 @@ export async function resolveSpotifyLink() {
     if (!res.ok) {
       const err = await res.json().catch(() => ({}));
       if (err.error === 'EDITORIAL_PLAYLIST') throw new Error('EDITORIAL_PLAYLIST');
+      if (err.error === 'RATE_LIMITED') throw new Error(`RATE_LIMITED:${err.retryAfter || 30}`);
       throw new Error(err.error || err.message || `HTTP ${res.status}`);
     }
     const data = await res.json();
@@ -79,6 +80,17 @@ export async function resolveSpotifyLink() {
       inner.innerHTML = `<div style="color:var(--danger);padding:16px;background:var(--surface);border-radius:10px">Zeitüberschreitung — der Server hat nicht rechtzeitig geantwortet. Läuft das Backend?</div>`;
       return;
     }
+    if (e.message.startsWith('RATE_LIMITED:')) {
+      const secs = parseInt(e.message.split(':')[1], 10) || 30;
+      const mins = secs >= 60 ? `${Math.ceil(secs / 60)} Min.` : `${secs}s`;
+      inner.innerHTML = `<div style="color:var(--text);padding:16px;background:var(--surface);border-radius:10px;border-left:3px solid var(--warning,#f59e0b)">
+        <div style="font-weight:600;margin-bottom:6px">⏳ Spotify Rate Limit</div>
+        <div style="font-size:13px;line-height:1.5;color:var(--text2)">
+          Spotify hat zu viele Anfragen erhalten. Bitte in ca. <strong>${mins}</strong> erneut versuchen.
+        </div>
+      </div>`;
+      return;
+    }
     if (e.message === 'EDITORIAL_PLAYLIST') {
       inner.innerHTML = `<div style="padding:16px;background:var(--surface);border-radius:10px;border-left:3px solid #1DB954">
         <div style="font-weight:600;margin-bottom:10px;color:#1DB954">💡 Editorial Playlist erkannt</div>