Add BatchRecActionViewResponse and update InvokeAsync

Introduce the `BatchRecActionViewResponse` class to represent the
result of batch RecAction invocations, including total actions
processed and exceptions encountered.

Update `InvokeAsync` methods in `RecActionApi` to return a
`BatchRecActionViewResponse` instead of `void`. Modify the
implementation to deserialize API responses into this new class.

Add XML documentation for the updated return type and use
conditional compilation to handle nullable reference types
for .NET Framework and other target frameworks.

src/ReC.Client/Api/BatchRecActionViewResponse.cs

@@ -0,0 +1,14 @@
+namespace ReC.Client.Api
+{
+    /// <summary>
+    /// Represents the result of a batch RecAction invocation.
+    /// </summary>
+    public class BatchRecActionViewResponse
+    {
+        /// <summary>Total number of actions that were processed.</summary>
+        public int TotalActionCount { get; set; }
+
+        /// <summary>Number of actions that resulted in an exception.</summary>
+        public int ActionExceptionCount { get; set; }
+    }
+}