refactor(entities/Font): named public API and expose stores via root barrel

Stores were only reachable by deep-importing $entities/Font/model, so
consumers reached past the slice public API (FSD anti-pattern D, B-3/D-2).

- convert the Font barrels (root, model, model/store, model/types) to
  explicit named exports with export/export type split (B-1)
- re-export the lazy store accessors/classes from the root barrel so the
  entity public API is complete and inert at import (construction stays
  lazy; the root already loads tanstack via ./ui)
- repoint all consumers (SampleList, SampleListSection, FontList,
  comparisonStore, bindings) from $entities/Font/model to $entities/Font

src/entities/Font/model/store/index.ts

@@ -1,9 +1,12 @@
 // Font lifecycle manager (browser-side load + cache + eviction)
-export * from './fontLifecycleManager/fontLifecycleManager.svelte';
+export {
+    __resetFontLifecycleManager,
+    FontLifecycleManager,
+    getFontLifecycleManager,
+} from './fontLifecycleManager/fontLifecycleManager.svelte';
 
 // Paginated catalog
 export { getFontCatalog } from './fontCatalogStore/fontCatalogStore.svelte';
-
 export type { FontCatalogStore } from './fontCatalogStore/fontCatalogStore.svelte';
 
 // Batch fetch by IDs (detail-cache seeding)