perf: reduce software rendering overhead for NVIDIA+Wayland

Targeted optimizations for the DMABuf-disabled rendering path where
every frame is software-composited:

- Replace infinite CSS scroll-text animation with transition-based
  cycle that only repaints during active scroll, not during pauses
- Remove CSS mask-image on scrolling text (mask + animation was the
  single most expensive continuous repaint)
- Replace wa-icon in track rows with inline SVG — eliminates 30-50
  shadow DOM trees (each with SVG fetch/parse) during scroll
- Remove hover transitions on album cards, artist cards, genre cards,
  fav icons, queue remove buttons — each transition was causing
  per-frame software repaints
- Use visibility:hidden instead of opacity:0 for queue remove button
  (binary switch vs per-frame alpha blend)
- Add decoding=async to now-playing cover art images (prevents
  main-thread blocking during image decode on track change)
- Add contain:strict to fixed-height track rows (33px) and queue
  items (49px) — browser skips size contribution calculations

frontend/src/components/artists-view/artists-view.ts

@@ -245,9 +245,7 @@ export class ArtistsView
                 padding: 5px;
                 border-radius: 8px;
                 cursor: pointer;
-                transition:
-                    background-color 0.15s ease,
-                    transform 0.15s ease;
+                /* transitions removed — software rendering repaints per frame */
                 overflow: hidden;
             }