<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Enforced signup restrictions for OAuth login based on configuration settings. Users will not be able to sign up via OAuth if signup is disabled by the administrator.
- **Bug Fixes**
- Improved error handling during OAuth login when signup is not permitted.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->