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/cover-grid/cover-grid-styles.ts

@@ -9,6 +9,7 @@ const gridStyles = css`
         flex-direction: column;
         overflow: hidden;
         position: relative;
+        contain: layout style;
     }
 
     /* ========================================
@@ -129,6 +130,8 @@ const gridStyles = css`
         flex: 1;
         position: relative;
         overflow-y: auto;
+        contain: paint;
+        will-change: transform;
     }
 
     /* ========================================
@@ -146,6 +149,8 @@ const gridStyles = css`
             transform 0.15s ease;
         box-sizing: border-box;
         width: var(--card-width, 176px);
+        content-visibility: auto;
+        contain-intrinsic-size: auto var(--card-width, 176px) auto calc(var(--card-width, 176px) + 40px);
     }
 
     .album-card:hover {