feat(fonts): implement Phase 2 - Unified Font Store

- Implemented UnifiedFontStore extending BaseFontStore
- Added pagination support with derived metadata
- Added provider-specific shortcuts (setProvider, setCategory, etc.)
- Added pagination methods (nextPage, prevPage, goToPage)
- Added category getter shortcuts (sansSerifFonts, serifFonts, etc.)
- Updated store exports to include unified store
- Fixed typo in googleFontsStore.svelte.ts (createGoogleFontsStore)

Phase 2/7: Proxy API Integration for GlyphDiff

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

@@ -6,18 +6,29 @@
  * Single export point for the unified font store infrastructure.
  */
 
-// export {
-//     createUnifiedFontStore,
-//     UNIFIED_FONT_STORE_KEY,
-//     type UnifiedFontStore,
-// } from './unifiedFontStore.svelte';
+// Primary store (unified)
+export {
+    createUnifiedFontStore,
+    type UnifiedFontStore,
+    unifiedFontStore,
+} from './unifiedFontStore.svelte';
 
+// Applied fonts manager (CSS loading - unchanged)
+export { appliedFontsManager } from './appliedFontsStore/appliedFontsStore.svelte';
+
+// Selected fonts store (user selection - unchanged)
+export { selectedFontsStore } from './selectedFontsStore/selectedFontsStore.svelte';
+
+// DEPRECATED: Fontshare store (will be removed in Phase 6)
 export {
     createFontshareStore,
     type FontshareStore,
     fontshareStore,
 } from './fontshareStore.svelte';
 
-export { appliedFontsManager } from './appliedFontsStore/appliedFontsStore.svelte';
-
-export { selectedFontsStore } from './selectedFontsStore/selectedFontsStore.svelte';
+// DEPRECATED: Google Fonts store (will be removed in Phase 6)
+export {
+    createGoogleFontsStore,
+    type GoogleFontsStore,
+    googleFontsStore,
+} from './googleFontsStore.svelte';