perf(14-01): add GPU promotion and containment to all scroll containers

- contain: layout style on :host of all 6 scroll-heavy components
- contain: paint + will-change: transform on all scroll containers for GPU compositing
- content-visibility: auto + contain-intrinsic-size on .album-card for off-screen skip
- cover-grid, track-list, queue-panel, artists-view, genres-view, playlist-view

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

@@ -223,12 +223,15 @@ export class ArtistsView
                 flex-direction: column;
                 overflow: hidden;
                 position: relative;
+                contain: layout style;
             }
 
             .grid-scroll-container {
                 flex: 1;
                 overflow-y: auto;
                 overflow-x: hidden;
+                contain: paint;
+                will-change: transform;
             }
 
             lit-virtualizer {