Upgraded projects to .NET 9.0 and added new projects `KBR.Cache`, `KBR.Shared`, and `KBR.Shared.Lite` to the solution. Introduced JWT authentication and OTP handling with new models, services, and configuration options. Updated database schema with new entities `Users` and `RefreshTokens`, and added migrations for schema changes. Implemented caching strategies using `AppDistributedCache` with support for in-memory, SQL Server, and Redis. Enhanced email handling with `MailHelpers` for domain replacement. Updated controllers, repositories, and configuration files to support new features.
