Remove deprecated middleware and update component tests for branding and auth enhancements

- Deleted `middleware.disabled.ts` as it is no longer needed.
- Refactored `HeroSection` and `HomePage` tests to align with updated branding and messaging.
- Modified `DemoCredentialsModal` to support auto-filled demo credentials in login links.
- Mocked `ThemeToggle`, `LocaleSwitcher`, and `DemoCredentialsModal` in relevant tests.
- Updated admin tests to use `QueryClientProvider` and refactored API mocks for `AdminPage`.
- Replaced test assertions for stats section and badges with new branding content.

frontend/tests/components/home/DemoCredentialsModal.test.tsx

@@ -156,10 +156,16 @@ describe('DemoCredentialsModal', () => {
     render(<DemoCredentialsModal open={true} onClose={mockOnClose} />);
 
     const loginAsUserLink = screen.getByRole('link', { name: /login as user/i });
-    expect(loginAsUserLink).toHaveAttribute('href', '/login');
+    expect(loginAsUserLink).toHaveAttribute(
+      'href',
+      '/login?email=demo@example.com&password=Demo123!'
+    );
 
     const loginAsAdminLink = screen.getByRole('link', { name: /login as admin/i });
-    expect(loginAsAdminLink).toHaveAttribute('href', '/login');
+    expect(loginAsAdminLink).toHaveAttribute(
+      'href',
+      '/login?email=admin@example.com&password=Admin123!'
+    );
   });
 
   it('calls onClose when login link is clicked', () => {