VS-05 Authentication Happy Path (Login/Logout + Session Persistence)

[CherryClairette]

What to build

Implement an end-to-end authentication happy path covering login, logout, session restore on refresh, and protected route behavior. This slice should be demoable with backend or mock auth endpoints and include baseline failure handling.

Acceptance criteria

• User can log in and be redirected to an authenticated area
• User can log out and session data is cleared correctly
• Refreshing the page restores valid session state
• Invalid or expired auth state redirects to login gracefully
• Core auth flow has unit or integration tests

Blocked by

VS-02 React + TypeScript + Quality Baseline