perf: inline SVGs, memoize grid slices, batch store notifications

- Replace wa-icon shadow DOM with inline SVG in queue-panel (xmark)
  and album-dropdown (fav icons) to eliminate per-item shadow roots
- Memoize getBeforeEntries/getAfterEntries in cover-grid to prevent
  .slice() creating new array refs that trigger virtualizer relayout
- Remove transition: scale and border-radius from album cards to
  avoid per-frame repaints and anti-aliased path clipping
- Add queueMicrotask batching to player-store and favorites-store
  notify() to coalesce rapid-fire updates into single renders

frontend/src/components/cover-grid/cover-grid-styles.ts

@@ -141,9 +141,10 @@ const gridStyles = css`
         display: flex;
         flex-direction: column;
         cursor: pointer;
-        border-radius: 8px;
         padding: 5px;
-        /* transitions removed — software rendering repaints per frame */
+        /* border-radius removed — forces anti-aliased path clipping on
+           every paint of every visible card; cover image retains its own
+           4px radius via .cover-container */
         box-sizing: border-box;
         width: var(--card-width, 176px);
     }
@@ -169,7 +170,7 @@ const gridStyles = css`
         border-radius: 4px;
         overflow: hidden;
         background-color: var(--yj-bg-surface, #282828);
-        transition: scale 0.15s ease;
+        /* transition removed — software rendering repaints per frame */
     }
 
     .album-card.selected .cover-container {
@@ -202,7 +203,7 @@ const gridStyles = css`
         margin-top: 4px;
         min-width: 0;
         text-align: center;
-        transition: scale 0.15s ease;
+        /* transition removed — software rendering repaints per frame */
     }
 
     .album-card.selected .album-info {