User Logout

[sydneyrd]

User Logout
Description: Implement logout functionality that clears session on both frontend and backend.
AC:
Frontend: Logout button in header/menu
Frontend: Confirmation modal before logout
Backend: Endpoint to invalidate session
Backend: Clear any cached user data
Frontend: Clear local storage/session storage
Frontend: Redirect to login page after logout
Frontend: Show success message after logout
Tech notes: