Add JWT, OTP, and caching features

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.

Shared/KBR.Shared/Cache/IAppDistributedCache.cs

@@ -0,0 +1,27 @@
+using Microsoft.Extensions.Caching.Distributed;
+
+namespace KBR.Shared.Cache
+{
+    public interface IAppDistributedCache
+    {
+        T Get<T>(string key)
+           where T : class;
+
+        Task<T> GetAsync<T>(string key, CancellationToken cancellationToken = default)
+           where T : class;
+
+        void Remove(string key);
+
+        Task RemoveAsync(string key, CancellationToken cancellationToken = default);
+
+        void Set<T>(string key, T obj, DistributedCacheEntryOptions? options = default);
+
+        Task SetAsync<T>(string key, T obj, DistributedCacheEntryOptions? options = default, CancellationToken cancellationToken = default);
+
+        TItem GetOrCreate<TItem>(string key, Func<TItem> factory)
+           where TItem : class;
+
+        Task<TItem> GetOrCreateAsync<TItem>(string key, Func<Task<TItem>> factory, CancellationToken cancellationToken = default)
+            where TItem : class;
+    }
+}