Refactored AuthController to improve attribute usage and code clarity. Added three endpoints: /auth/me (user info), /auth/login (NTLM/Negotiate authentication with user info or 401), and /auth/status (authenticated user status). Responses are now more structured and informative. Applied [Authorize] only to relevant endpoints. Improved code organization and documentation.
Introduced AuthController secured with [Authorize] attribute.
Provides a GET /auth/me endpoint that returns the authenticated
user's identity details and claims.
