Adds TOTP (Time-based One-Time Password) two-factor authentication support including:
- New TOTP service with secret generation, QR code provisioning, and code verification
- New auth endpoints for enrollment, verification, status, and backup code management
- New TOTP authentication method type and user methods for TOTP management
- Backup codes generation and verification for account recovery
- Updated OIDC endpoints with timezone-aware datetime handling and RFC-compliant responses
- Added "roles" scope support for OIDC userinfo and ID tokens
- New pyotp dependency for TOTP operations
- Comprehensive unit tests for TOTP service
