This PR replaces 10 separate useState calls inside authkit-provider.tsx with a single discriminated union:

type AuthState =
 | {
     status: 'loading';
   }
 | { status: 'unauthenticated'; data: Omit<NoUserInfo, 'accessToken'> }
 | { status: 'authenticated'; data: Omit<UserInfo, 'accessToken'> };

This brings two benefits to the codebase:

• Makes it impossible for anyone to unintentionally create an invalid auth state combination (which is possible now).
• Makes it immediately clear which auth state is being handled at any point in the code.

Note: There are no changes to the public API. All existing tests pass.