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/index.ts

@@ -1,6 +1,51 @@
-export * from './const/const';
+export {
+    DEFAULT_FONT_SIZE,
+    DEFAULT_FONT_WEIGHT,
+    DEFAULT_LETTER_SPACING,
+    DEFAULT_LINE_HEIGHT,
+    FONT_SIZE_STEP,
+    FONT_WEIGHT_STEP,
+    LETTER_SPACING_STEP,
+    LINE_HEIGHT_STEP,
+    MAX_FONT_SIZE,
+    MAX_FONT_WEIGHT,
+    MAX_LETTER_SPACING,
+    MAX_LINE_HEIGHT,
+    MIN_FONT_SIZE,
+    MIN_FONT_WEIGHT,
+    MIN_LETTER_SPACING,
+    MIN_LINE_HEIGHT,
+    VIRTUAL_INDEX_NOT_LOADED,
+} from './const/const';
 
-export { getFontCatalog } from './store';
+// Stores (lazy accessors + classes)
+export {
+    __resetFontLifecycleManager,
+    FontLifecycleManager,
+    FontsByIdsStore,
+    getFontCatalog,
+    getFontLifecycleManager,
+} from './store';
+export type { FontCatalogStore } from './store';
 
-export * from './store';
-export * from './types';
+export type {
+    FilterGroup,
+    FilterType,
+    FontCategory,
+    FontCollectionFilters,
+    FontCollectionSort,
+    FontCollectionState,
+    FontFeatures,
+    FontFilters,
+    FontLoadRequestConfig,
+    FontLoadStatus,
+    FontMetadata,
+    FontProvider,
+    FontStyleUrls,
+    FontSubset,
+    FontVariant,
+    FontWeight,
+    FontWeightItalic,
+    UnifiedFont,
+    UnifiedFontVariant,
+} from './types';

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)

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

@@ -23,4 +23,7 @@ export type {
     FontCollectionState,
 } from './store';
 
-export * from './store/fontLifecycle';
+export type {
+    FontLoadRequestConfig,
+    FontLoadStatus,
+} from './store/fontLifecycle';