Auth: Implement User Registration & Login Flow

[cliffdoyle]

A user must be able to create an account and log in securely. Sessions are managed by Redis.

Backend Tasks:

• Create a /api/register endpoint that takes user details, hashes the password (use bcrypt), and saves to the users table.
• Create a /api/login endpoint that validates credentials.
• On successful login, generate a random session token, store {user_id, role} in Redis with the token as the key, and set a 24h expiry.
• Create an authentication middleware that protects routes. It must check for a Authorization: Bearer header, validate the token against Redis, and pass user info into the request context.

Frontend Tasks:

• Create a RegisterPage.jsx component with a form that calls the /api/register endpoint.
• Create a LoginPage.jsx component with a form that calls the /api/login endpoint.
• On successful login, store the session token in a secure HttpOnly cookie or localStorage.
• Configure your Axios instance to automatically include the token in all future requests.
• Implement a ProtectedRoute component that redirects to /login if no user is authenticated.