fix(web): Deezer artist images + rename the search label

- Search artist cards now use the Deezer artist picture directly (Deezer artists carry
  a photo, unlike iTunes entities) instead of a null image + an extra album lookup;
  the lookup stays only as a fallback when no picture is present.
- Non-local (Deezer) artist pages: fetch the Deezer artist picture (/artist/{id}) for
  the hero photo, which was blank because getArtistImage only runs for Navidrome artists.
- Label "iTunes Künstler" → "Deezer Künstler".

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/views/search.js

@@ -130,9 +130,10 @@ export async function doGlobalSearch(q) {
       const s = mkSection('Künstler');
       const row = document.createElement('div'); row.className = 'scroll-row';
       artists.forEach(a => {
-        const c = makeCard(a.artistName, 'iTunes Künstler', null, '🎤');
+        const c = makeCard(a.artistName, 'Deezer Künstler', a.artworkUrl100 || null, '🎤');
         c.onclick = () => loadItunesArtistResults(a.artistId, a.artistName);
         row.appendChild(c);
+        if (a.artworkUrl100) return; // Deezer artists already carry a photo — no extra lookup
         itunesSearch(a.artistName,'album',1).then(res => {
           if(!res[0]) return;
           const imgUrl = res[0].artworkUrl100?.replace('100x100','300x300');