fix: normalize title comparison in iTunes lookup to handle Spotify dash-variants vs iTunes paren-variants

backend/lib/metadata.js

@@ -67,20 +67,38 @@ async function fetchLyrics(artist, title, album) {
   } catch { return null; }
 }
 
+// Normalize a track title for comparison: unify variant suffixes so that
+// "don't rush - slowed" and "don't rush (slowed)" are treated as equal.
+function normalizeTitle(s) {
+  return (s || '')
+    .toLowerCase()
+    .trim()
+    // convert "title - variant" → "title (variant)" so both forms compare equal
+    .replace(/\s+-\s+([^-]+)$/, ' ($1)')
+    // strip all remaining parens/brackets content for the base comparison
+    .replace(/[\[(（][^\]）)]*[\]）)]/g, '')
+    .trim();
+}
+
 // iTunes track lookup — fills in album, year, trackNum, totalTracks, genre when missing
 async function lookupItunesTrackMeta(artist, title) {
   try {
-    const url = `https://itunes.apple.com/search?term=${encodeURIComponent(artist + ' ' + title)}&media=music&entity=musicTrack&limit=5&country=us&explicit=Yes`;
+    // Search with base title (strip variant suffix) for better iTunes hit rate —
+    // e.g. "don't rush - slowed" → search "don't rush" so iTunes finds the single
+    const baseTitle = title.replace(/\s*[-–]\s*\S[^-]*$/, '').trim() || title;
+    const searchTitle = baseTitle !== title ? baseTitle : title;
+    const url = `https://itunes.apple.com/search?term=${encodeURIComponent(artist + ' ' + searchTitle)}&media=music&entity=musicTrack&limit=10&country=us&explicit=Yes`;
     const results = await new Promise((resolve, reject) => {
       https.get(url, res => {
         let d = ''; res.on('data', c => d += c);
         res.on('end', () => { try { resolve(JSON.parse(d).results || []); } catch { reject(new Error('parse')); } });
       }).on('error', reject);
     });
-    const norm = s => s?.toLowerCase().trim() || '';
-    const match = results.find(t =>
-      norm(t.trackName) === norm(title) &&
-      norm(t.artistName).split(' ')[0] === norm(artist).split(' ')[0]
+    const normT  = normalizeTitle(title);
+    const normA  = (artist || '').toLowerCase().trim();
+    const match  = results.find(t =>
+      normalizeTitle(t.trackName) === normT &&
+      (t.artistName || '').toLowerCase().trim().split(' ')[0] === normA.split(' ')[0]
     );
     if (!match) return {};
     return {