Update tests and e2e files to support locale-based routing

- Replaced static paths with dynamic locale subpaths (`/[locale]/*`) in imports, URLs, and assertions across tests.
- Updated `next-intl` mocks for improved compatibility with `locale`-aware components.
- Standardized `page.goto` and navigation tests with `/en` as the base locale for consistency.

frontend/tests/app/admin/layout.test.tsx

@@ -5,7 +5,7 @@
 
 import { render, screen } from '@testing-library/react';
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
-import AdminLayout from '@/app/admin/layout';
+import AdminLayout from '@/app/[locale]/admin/layout';
 import { useAuth } from '@/lib/auth/AuthContext';
 
 // Mock dependencies

frontend/tests/app/admin/organizations/[id]/members/page.test.tsx

@@ -3,7 +3,7 @@
  */
 
 import { render, screen } from '@testing-library/react';
-import OrganizationMembersPage from '@/app/admin/organizations/[id]/members/page';
+import OrganizationMembersPage from '@/app/[locale]/admin/organizations/[id]/members/page';
 
 // Mock Next.js Link
 jest.mock('next/link', () => ({

frontend/tests/app/admin/organizations/page.test.tsx

@@ -4,7 +4,7 @@
  */
 
 import { render, screen } from '@testing-library/react';
-import AdminOrganizationsPage from '@/app/admin/organizations/page';
+import AdminOrganizationsPage from '@/app/[locale]/admin/organizations/page';
 
 // Mock the entire OrganizationManagementContent component
 jest.mock('@/components/admin/organizations/OrganizationManagementContent', () => ({

frontend/tests/app/admin/page.test.tsx

@@ -4,7 +4,7 @@
  */
 
 import { render, screen } from '@testing-library/react';
-import AdminPage from '@/app/admin/page';
+import AdminPage from '@/app/[locale]/admin/page';
 import { useAdminStats } from '@/lib/api/hooks/useAdmin';
 
 // Mock the useAdminStats hook

frontend/tests/app/admin/settings/page.test.tsx

@@ -4,7 +4,7 @@
  */
 
 import { render, screen } from '@testing-library/react';
-import AdminSettingsPage from '@/app/admin/settings/page';
+import AdminSettingsPage from '@/app/[locale]/admin/settings/page';
 
 describe('AdminSettingsPage', () => {
   it('renders page title', () => {

frontend/tests/app/admin/users/page.test.tsx

@@ -5,7 +5,7 @@
 
 import { render, screen } from '@testing-library/react';
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
-import AdminUsersPage from '@/app/admin/users/page';
+import AdminUsersPage from '@/app/[locale]/admin/users/page';
 import { useAuth } from '@/lib/auth/AuthContext';
 import { useAdminUsers } from '@/lib/api/hooks/useAdmin';