refactor(shared/api): lazify queryClient to remove eager-construction footgun

queryClient.ts constructed the TanStack client at module eval but was not
in the sideEffects allowlist, so Rollup treated the module as pure — safe
only while a value-importer keeps it alive (D-3).

- replace the eager `queryClient` singleton with a memoized getQueryClient()
  factory; construction is deferred to first call
- the module is now genuinely side-effect-free, so no sideEffects exception
  is needed and construction can never be legally tree-shaken away
- route all consumers through getQueryClient() (QueryProvider as first
  caller; stores via class fields/observers; tests via a local alias; the
  fontCatalogStore spec mock now overrides getQueryClient)

src/entities/Font/api/proxy/proxyFonts.test.ts

@@ -19,7 +19,9 @@ vi.mock('$shared/api/api', () => ({
 }));
 
 import { api } from '$shared/api/api';
-import { queryClient } from '$shared/api/queryClient';
+import { getQueryClient } from '$shared/api/queryClient';
+
+const queryClient = getQueryClient();
 import { fontKeys } from '$shared/api/queryKeys';
 import { FontResponseError } from '../../lib/errors/errors';
 import {

src/entities/Font/api/proxy/proxyFonts.ts

@@ -11,7 +11,7 @@
  */
 
 import { api } from '$shared/api/api';
-import { queryClient } from '$shared/api/queryClient';
+import { getQueryClient } from '$shared/api/queryClient';
 import { fontKeys } from '$shared/api/queryKeys';
 import { buildQueryString } from '$shared/lib/utils';
 import type { QueryParams } from '$shared/lib/utils';
@@ -26,7 +26,7 @@ import type { UnifiedFont } from '../../model/types';
  */
 export function seedFontCache(fonts: UnifiedFont[]): void {
     fonts.forEach(font => {
-        queryClient.setQueryData(fontKeys.detail(font.id), font);
+        getQueryClient().setQueryData(fontKeys.detail(font.id), font);
     });
 }