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/auth/LoginForm.test.tsx

@@ -32,11 +32,15 @@ jest.mock('@/lib/api/hooks/useAuth', () => ({
   useLogin: () => mockUseLogin(),
 }));
 
+// Mock router
 // Mock router
 jest.mock('next/navigation', () => ({
   useRouter: () => ({
     push: jest.fn(),
   }),
+  useSearchParams: () => ({
+    get: jest.fn(),
+  }),
 }));
 
 // Mock auth store