perf(08-02): migrate cover-grid, artists-view, and genres-view virtualizers to repeat() directive

- cover-grid: all 3 virtualizers (single, before-split, after-split) use repeat() with album.ID key
- artists-view uses repeat() with artist.ID key
- genres-view uses repeat() with genre.name key
- Removed gridKeyFunction (now inlined in repeat calls)
- Removed .renderItem and .keyFunction properties from all virtualizers

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

@@ -10,6 +10,7 @@ import type {
     VisibilityChangedEvent,
 } from '@lit-labs/virtualizer';
 import { grid } from '@lit-labs/virtualizer/layouts/grid.js';
+import { repeat } from 'lit/directives/repeat.js';
 import { GetTracksByGenre } from '@go/library/Library';
 import type { library } from '@go/models';
 import { LibraryController } from '@store/controllers/library-controller';
@@ -1168,13 +1169,13 @@ export class GenresView
             >
                 <lit-virtualizer
                     .items=${entries}
-                    .renderItem=${(
-                        entry: GenreEntry,
-                    ) =>
-                        this.renderGenreCard(entry)}
                     .layout=${this.gridLayout}
                     @visibilityChanged=${this.onVisibilityChanged}
-                ></lit-virtualizer>
+                >${repeat(
+                    entries,
+                    (entry) => entry.genre.name,
+                    (entry) => this.renderGenreCard(entry),
+                )}</lit-virtualizer>
             </div>
             ${this.renderContextMenu()}
         `;