fix: bump SW cache to v39, split multi-artists by ' / ', name-search fallback for artist nav

- sw.js: ns-v38 → ns-v39 forces PWA cache clear so previous fixes take effect
- components: split s.artist by ' / ' in makeSongItem — each part becomes its
  own clickable link; noArtistLink turns all parts into plain text
- views: s_goArtist searches Navidrome by name when no artistId is available
  (needed for secondary artists that only have the primary artistId in the song)

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

src/components.js

@@ -32,10 +32,14 @@ export function makeSongItem(s, idx, list, { noArtistLink = false, noAlbumLink =
   if(s.starred && !s._starred) s._starred = true;
   el.className = 'song-item' + (S.queue[S.qIdx]?.id === s.id ? ' playing' : '');
   const cv = coverUrl(s.coverArt, 60);
-  const artistHtml = s.artistId||s.artist
-    ? (noArtistLink
-        ? `<span style="color:var(--text2)">${esc(s.artist||'')}</span>`
-        : `<span class="song-link" onclick="event.stopPropagation();s_goArtist(event,'${esc(s.artist||'')}','${s.artistId||''}')">${esc(s.artist||'')}</span>`)
+  const artistParts = (s.artist || '').split(' / ').filter(Boolean);
+  const artistHtml = artistParts.length
+    ? artistParts.map((name, i) => {
+        const aid = i === 0 ? (s.artistId || '') : '';
+        return noArtistLink
+          ? `<span style="color:var(--text2)">${esc(name)}</span>`
+          : `<span class="song-link" onclick="event.stopPropagation();s_goArtist(event,'${esc(name)}','${aid}')">${esc(name)}</span>`;
+      }).join('<span style="color:var(--text3)"> / </span>')
     : '';
   const albumHtml = !noAlbumLink && (s.albumId||s.album)
     ? `<span style="color:var(--text3)"> · </span><span class="song-link" onclick="event.stopPropagation();s_goAlbum(event,'${s.albumId||''}','${esc(s.album||'')}','${esc(s.artist||'')}','${s.artistId||''}')">${esc(s.album||'')}</span>`