Refactor to enforce AuthContext usage over useAuthStore and improve test stability

- Replaced `useAuthStore` with `useAuth` from `AuthContext` across frontend components and tests to ensure dependency injection compliance.
- Enhanced E2E test stability by delaying navigation until the auth context is fully initialized.
- Updated Playwright configuration to use a single worker to prevent mock conflicts.
- Refactored test setup to consistently inject `AuthProvider` for improved isolation and mocking.
- Adjusted comments and documentation to clarify dependency injection and testability patterns.

frontend/tests/components/auth/AuthInitializer.test.tsx

@@ -5,6 +5,7 @@
 
 import { render, waitFor } from '@testing-library/react';
 import { AuthInitializer } from '@/components/auth/AuthInitializer';
+import { AuthProvider } from '@/lib/auth/AuthContext';
 import { useAuthStore } from '@/lib/stores/authStore';
 
 // Mock the auth store
@@ -28,13 +29,21 @@ describe('AuthInitializer', () => {
 
   describe('Initialization', () => {
     it('renders nothing (null)', () => {
-      const { container } = render(<AuthInitializer />);
+      const { container } = render(
+        <AuthProvider>
+          <AuthInitializer />
+        </AuthProvider>
+      );
 
       expect(container.firstChild).toBeNull();
     });
 
     it('calls loadAuthFromStorage on mount', async () => {
-      render(<AuthInitializer />);
+      render(
+        <AuthProvider>
+          <AuthInitializer />
+        </AuthProvider>
+      );
 
       await waitFor(() => {
         expect(mockLoadAuthFromStorage).toHaveBeenCalledTimes(1);
@@ -42,14 +51,22 @@ describe('AuthInitializer', () => {
     });
 
     it('does not call loadAuthFromStorage again on re-render', async () => {
-      const { rerender } = render(<AuthInitializer />);
+      const { rerender } = render(
+        <AuthProvider>
+          <AuthInitializer />
+        </AuthProvider>
+      );
 
       await waitFor(() => {
         expect(mockLoadAuthFromStorage).toHaveBeenCalledTimes(1);
       });
 
       // Force re-render
-      rerender(<AuthInitializer />);
+      rerender(
+        <AuthProvider>
+          <AuthInitializer />
+        </AuthProvider>
+      );
 
       // Should still only be called once (useEffect dependencies prevent re-call)
       expect(mockLoadAuthFromStorage).toHaveBeenCalledTimes(1);

frontend/tests/lib/api/hooks/useUser.test.tsx

@@ -7,6 +7,7 @@ import { renderHook, waitFor } from '@testing-library/react';
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
 import { useUpdateProfile } from '@/lib/api/hooks/useUser';
 import { useAuthStore } from '@/lib/stores/authStore';
+import { AuthProvider } from '@/lib/auth/AuthContext';
 import * as apiClient from '@/lib/api/client';
 
 // Mock dependencies
@@ -32,7 +33,9 @@ describe('useUser hooks', () => {
 
   const wrapper = ({ children }: { children: React.ReactNode }) => (
     <QueryClientProvider client={queryClient}>
-      {children}
+      <AuthProvider>
+        {children}
+      </AuthProvider>
     </QueryClientProvider>
   );