IA-934 : [FEATURE] Two-Factor Authentication (2FA) - User Management Service

What

Implemented two-factor authentication (2FA) for user login in the user management service.

Changes

New DTOs:

• TwoFactorPreferenceRequest — enable/disable 2FA and set method (EMAIL/SMS)
• TwoFactorVerifyRequest — verify OTP code
• TwoFactorStatusResponse — return current 2FA status
• LoginResponse — unified login response supporting both 2FA and non-2FA flows

UserService / UserServiceImpl:

• Added authenticateBoWith2FA, authenticateApWith2FA, authenticateAeWith2FA
• Added verifyTwoFactorCode — validates OTP and returns JWT
• Added saveTwoFactorPreference — enable/disable 2FA per user
• Added getTwoFactorStatus — returns current 2FA config for user

UserController:

• Login endpoints now return LoginResponse instead of AuthenticationResponse
• Added POST /two-factor/verify
• Added PUT /two-factor/setup
• Added GET /two-factor/status

ApiPaths:

• Added TWO_FACTOR_VERIFY, TWO_FACTOR_SETUP, TWO_FACTOR_STATUS

Flow

1. User logs in → credentials verified
2. If 2FA disabled → JWT returned directly
3. If 2FA enabled → OTP sent by email, twoFactorRequired: true returned
4. User submits OTP → JWT returned after validation