fix: artist hero banner taller on desktop, fix right-side overlay bleed

- Hero height 220px mobile → 320px desktop (min-width: 769px)
- Larger artist name (46px) and more padding on desktop
- Overlay gradient now also darkens the right edge instead of fading to transparent

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

src/views.js

@@ -264,7 +264,7 @@ export async function loadArtistDetail(artist) {
   const img = imgRes.status === 'fulfilled' ? imgRes.value : null;
   if(img) {
     hero.style.background = `url('${img}') center/cover no-repeat`;
-    if(overlay) overlay.style.background = 'linear-gradient(to right,rgba(7,7,15,.9) 0%,rgba(7,7,15,.5) 60%,rgba(7,7,15,.2) 100%)';
+    if(overlay) overlay.style.background = 'linear-gradient(to right,rgba(7,7,15,.95) 0%,rgba(7,7,15,.35) 55%,rgba(7,7,15,.75) 100%)';
   }
 
   // ── Bio ──