refactor(font): replace fontLifecycleManager singleton with lazy accessor

Convert the eager fontLifecycleManager singleton to getFontLifecycleManager()
(+ __resetFontLifecycleManager for tests), so its AbortController/FontFace
bookkeeping is set up on first use rather than at module load. Update consumers
(FontVirtualList, FontList, SampleList) and resolve it once as a field in
comparisonStore; the comparisonStore mock now exposes getFontLifecycleManager.

src/entities/Font/model/store/fontLifecycleManager/fontLifecycleManager.svelte.ts

@@ -419,7 +419,18 @@ export class FontLifecycleManager {
     }
 }
 
+let _fontLifecycleManager: FontLifecycleManager | undefined;
+
 /**
- * Singleton instance — use throughout the application for unified font loading state.
+ * App-wide font lifecycle manager, created on first access. Lazy so its
+ * AbortController / FontFace bookkeeping isn't set up at module load.
  */
-export const fontLifecycleManager = new FontLifecycleManager();
+export function getFontLifecycleManager(): FontLifecycleManager {
+    return (_fontLifecycleManager ??= new FontLifecycleManager());
+}
+
+// test-only reset, so specs don't share loaded-font/eviction state
+export function __resetFontLifecycleManager() {
+    _fontLifecycleManager?.destroy();
+    _fontLifecycleManager = undefined;
+}