feat: Add SCIM 2.0 support for enterprise user provisioning

Implements SCIM 2.0 protocol for automated user and group provisioning from identity providers like Okta, Azure AD, and Google Workspace.

Backend changes:
- Add SCIM configuration with PersistentConfig for database persistence
- Implement SCIM 2.0 endpoints (Users, Groups, ServiceProviderConfig)
- Add bearer token authentication for SCIM requests
- Include comprehensive test coverage for SCIM functionality

Frontend changes:
- Add SCIM admin settings page with token generation
- Implement SCIM configuration management UI
- Add save functionality and proper error handling
- Include SCIM statistics display

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

README.md

@@ -31,6 +31,8 @@ For more information, be sure to check out our [Open WebUI Documentation](https:
 
 - 🛡️ **Granular Permissions and User Groups**: By allowing administrators to create detailed user roles and permissions, we ensure a secure user environment. This granularity not only enhances security but also allows for customized user experiences, fostering a sense of ownership and responsibility amongst users.
 
+- 🔄 **SCIM 2.0 Support**: Enterprise-grade user and group provisioning through SCIM 2.0 protocol, enabling seamless integration with identity providers like Okta, Azure AD, and Google Workspace for automated user lifecycle management.
+
 - 📱 **Responsive Design**: Enjoy a seamless experience across Desktop PC, Laptop, and Mobile devices.
 
 - 📱 **Progressive Web App (PWA) for Mobile**: Enjoy a native app-like experience on your mobile device with our PWA, providing offline access on localhost and a seamless user interface.