refactor(font): expose stores via model segment, not the top barrel

Re-exporting the store singletons (fontCatalogStore, fontLifecycleManager,
FontsByIdsStore) through entities/Font/index.ts meant every consumer of the
barrel eager-instantiated stores and pulled @tanstack/query-core — in dev,
test, and as retained code. Drop the store re-export from the top barrel;
keep the pure surface (types, constants, domain, lib, ui) there for
convenience. Consumers that need stores import $entities/Font/model.
Aligns with the BaseQueryStore carve-out: barrel by default, segment path
when it would drag a heavy or side-effectful dependency.

src/widgets/ComparisonView/ui/FontList/FontList.svelte

@@ -9,9 +9,11 @@ import {
     FontVirtualList,
     type UnifiedFont,
     VIRTUAL_INDEX_NOT_LOADED,
+} from '$entities/Font';
+import {
     fontCatalogStore,
     fontLifecycleManager,
-} from '$entities/Font';
+} from '$entities/Font/model';
 import { getSkeletonWidth } from '$shared/lib/utils';
 import {
     Button,