I'll help you create a complete authentication system where users can register, login, edit their profile (including email and password), and then login again with the updated credentials. Let me build this step by step.

I've created a complete authentication system that handles the exact flow you described:

Key Features:

1. User Registration: Complete signup form with validation
2. Login System: Secure login with email and password
3. Profile Editing: Users can update all their information including email and password
4. Automatic Re-authentication: When email or password is changed, users are automatically logged out and must login again with new credentials

How it Works:

1. Registration Flow:

   • User fills out signup form
   • Credentials and user data are stored in localStorage
   • User is automatically logged in after registration

2. Login Flow:

   • User enters email and password
   • System validates against stored credentials
   • Successful login redirects to dashboard

3. Profile Update Flow:

   • User can edit all profile information
   • When email or password is changed, both user data and credentials are updated
   • System automatically logs out user and redirects to login
   • User must login again with new credentials

4. Security Features:

   • Password confirmation validation
   • Form validation with error messages
   • Protected routes that require authentication
   • Automatic logout when credentials change

User Journey:

1. Sign Up → Automatically logged in → Dashboard
2. Edit Profile → Change email/password → Automatic Logout
3. Login Again with new credentials → Dashboard

The system uses localStorage for simplicity but maintains proper state management through React Context. When users update their email or password, they're immediately logged out and must authenticate again with their new credentials, ensuring security and data consistency.