fix(frontend): add extractErrorCode to all api.server vi.mock factories

All route spec files that mock $lib/shared/api.server were missing
extractErrorCode from the mock factory, causing a vitest "No export defined"
error after the refactor introduced the new export.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/routes/admin/ocr/[personId]/page.server.spec.ts

@@ -3,7 +3,10 @@ import { load } from './+page.server';
 
 const mockApi = { GET: vi.fn() };
 
-vi.mock('$lib/shared/api.server', () => ({ createApiClient: () => mockApi }));
+vi.mock('$lib/shared/api.server', () => ({
+	createApiClient: () => mockApi,
+	extractErrorCode: (e: unknown) => (e as { code?: string } | undefined)?.code
+}));
 
 beforeEach(() => vi.clearAllMocks());