feat: artist cards navigate-only (no play); add Top Songs + Shuffle buttons to artist detail page

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

styles.css

@@ -718,6 +718,10 @@ nav{flex:1;overflow-y:auto;padding:4px 10px}
 .np-drag-handle{width:100%;height:36px;display:flex;align-items:center;justify-content:center;cursor:grab;flex-shrink:0;touch-action:none}
 .np-drag-handle-bar{width:40px;height:4px;background:rgba(255,255,255,.25);border-radius:2px}
 
+.artist-card .play-overlay{display:none!important}
+.artist-action-bar{display:flex;gap:8px;margin-bottom:20px;flex-wrap:wrap}
+.artist-action-btn{display:flex;align-items:center;gap:6px;padding:9px 18px;border-radius:20px;border:1px solid var(--border2);background:var(--surface);color:var(--text);font-family:var(--font);font-size:13px;font-weight:600;cursor:pointer;transition:background .15s,border-color .15s}
+.artist-action-btn:hover{background:var(--surface2);border-color:var(--accent);color:var(--accent)}
 .artist-hero{height:220px;border-radius:14px;overflow:hidden;position:relative;margin-bottom:24px;background:linear-gradient(135deg,var(--surface2),var(--surface))}
 .artist-hero-overlay{position:absolute;inset:0;background:linear-gradient(to right,rgba(7,7,15,.85) 0%,transparent 100%);display:flex;align-items:flex-end;padding:20px 28px}
 .artist-hero-name{font-size:32px;font-weight:800;letter-spacing:-1px}