feat(utils): add generic buildQueryString utility

- Add type-safe buildQueryString function to /utils
- Support primitives, arrays, and optional values
- Proper URL encoding for special characters
- Add comprehensive tests (25 test cases, all passing)
- Update Google Fonts API client to use shared utility
- Update Fontshare API client to use shared utility
- Export utility from /utils/index.ts

Benefits:
- DRY - Single source of truth for query string logic
- Type-safe - Proper TypeScript support with QueryParams type
- Tested - Comprehensive test coverage
- Maintainable - One place to fix bugs

src/entities/Font/api/fontshare/fontshare.ts

@@ -12,11 +12,13 @@ import type {
     FontshareFont,
 } from '$entities/Font';
 import { api } from '$shared/api/api';
+import { buildQueryString } from '$shared/utils';
+import type { QueryParams } from '$shared/utils';
 
 /**
  * Fontshare API parameters
  */
-export interface FontshareParams {
+export interface FontshareParams extends QueryParams {
     /**
      * Filter by categories (e.g., ["Sans", "Serif", "Display"])
      */
@@ -47,36 +49,6 @@ export interface FontshareResponse extends FontshareApiModel {
     // Response structure matches FontshareApiModel
 }
 
-/**
- * Build query string from parameters
- */
-function buildQueryString(params: FontshareParams): string {
-    const searchParams = new URLSearchParams();
-
-    if (params.categories?.length) {
-        searchParams.append('categories', params.categories.join(','));
-    }
-
-    if (params.tags?.length) {
-        searchParams.append('tags', params.tags.join(','));
-    }
-
-    if (params.page) {
-        searchParams.append('page', String(params.page));
-    }
-
-    if (params.limit) {
-        searchParams.append('limit', String(params.limit));
-    }
-
-    if (params.search) {
-        searchParams.append('search', params.search);
-    }
-
-    const queryString = searchParams.toString();
-    return queryString ? `?${queryString}` : '';
-}
-
 /**
  * Fetch fonts from Fontshare API
  *

src/entities/Font/api/google/googleFonts.ts

@@ -8,11 +8,13 @@
  */
 
 import { api } from '$shared/api/api';
+import { buildQueryString } from '$shared/utils';
+import type { QueryParams } from '$shared/utils';
 
 /**
  * Google Fonts API parameters
  */
-export interface GoogleFontsParams {
+export interface GoogleFontsParams extends QueryParams {
     /**
      * Google Fonts API key (optional for public endpoints)
      */
@@ -66,40 +68,6 @@ export interface GoogleFontItem {
  */
 const GOOGLE_FONTS_API_URL = 'https://fonts.googleapis.com/v2/fonts' as const;
 
-/**
- * Build query string from parameters
- */
-function buildQueryString(params: GoogleFontsParams): string {
-    const searchParams = new URLSearchParams();
-
-    if (params.key) {
-        searchParams.append('key', params.key);
-    }
-
-    if (params.family) {
-        searchParams.append('family', params.family);
-    }
-
-    if (params.category) {
-        searchParams.append('category', params.category);
-    }
-
-    if (params.subset) {
-        searchParams.append('subset', params.subset);
-    }
-
-    if (params.sort) {
-        searchParams.append('sort', params.sort);
-    }
-
-    if (params.capability) {
-        searchParams.append('capability', params.capability);
-    }
-
-    const queryString = searchParams.toString();
-    return queryString ? `?${queryString}` : '';
-}
-
 /**
  * Fetch fonts from Google Fonts API
  *

src/entities/Font/api/index.ts

@@ -7,33 +7,33 @@
 export {
     fetchGoogleFontFamily,
     fetchGoogleFonts,
-} from './googleFonts';
+} from './google/googleFonts';
 export type {
     GoogleFontItem,
     GoogleFontsParams,
     GoogleFontsResponse,
-} from './googleFonts';
+} from './google/googleFonts';
 
 export {
     fetchAllFontshareFonts,
     fetchFontshareFontBySlug,
     fetchFontshareFonts,
-} from './fontshare';
+} from './fontshare/fontshare';
 export type {
     FontshareParams,
     FontshareResponse,
-} from './fontshare';
+} from './fontshare/fontshare';
 
 export {
     normalizeFontshareFont,
     normalizeFontshareFonts,
     normalizeGoogleFont,
     normalizeGoogleFonts,
-} from './normalize';
+} from './normalize/normalize';
 export type {
     FontFeatures,
     FontMetadata,
     FontStyleUrls,
     UnifiedFont,
     UnifiedFontVariant,
-} from './normalize';
+} from './normalize/normalize';

src/entities/Font/api/normalize/normalize.test.ts

@@ -1,17 +1,17 @@
 import type { FontshareFont } from '$entities/Font';
-import type { GoogleFontItem } from '$entities/Font/api/googleFonts';
-import type { UnifiedFont } from '$entities/Font/api/normalize';
-import {
-    normalizeFontshareFont,
-    normalizeFontshareFonts,
-    normalizeGoogleFont,
-    normalizeGoogleFonts,
-} from '$entities/Font/api/normalize';
 import {
     describe,
     expect,
     it,
 } from 'vitest';
+import type { GoogleFontItem } from '../google/googleFonts';
+import type { UnifiedFont } from './normalize';
+import {
+    normalizeFontshareFont,
+    normalizeFontshareFonts,
+    normalizeGoogleFont,
+    normalizeGoogleFonts,
+} from './normalize';
 
 describe('Font Normalization', () => {
     describe('normalizeGoogleFont', () => {

src/entities/Font/model/stores/fontCollectionStore.ts

@@ -8,10 +8,7 @@
  */
 
 import type { UnifiedFont } from '$entities/Font/api/normalize';
-import {
-    type CollectionCacheManager,
-    createCollectionCache,
-} from '$shared/fetch/collectionCache';
+import { createCollectionCache } from '$shared/fetch/collectionCache';
 import type {
     Readable,
     Writable,