Ensure proper disposal and add HttpExtensions class

Updated `InvokeRecActionCommand.cs` to use `using` statements for `HttpClient`, `HttpRequestMessage`, and `HttpResponseMessage` to prevent resource leaks.

Added a new `HttpExtensions.cs` file with a static `HttpExtensions` class as a placeholder for future HTTP-related extension methods. Included necessary `using` directives for potential LINQ, collections, and asynchronous programming.

src/ReC.Application/Common/HttpExtensions.cs

@@ -0,0 +1,11 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ReC.Application.Common;
+
+public static class HttpExtensions
+{
+}

src/ReC.Application/RecActions/Commands/InvokeRecActionCommand.cs

@@ -1,8 +1,6 @@
 using MediatR;
 using Microsoft.Extensions.Logging;
 using ReC.Application.Common.Dto;
-using System;
-using static System.Net.WebRequestMethods;
 
 namespace ReC.Application.RecActions.Commands;
 
@@ -25,7 +23,7 @@ public class InvokeRecActionCommandHandler(
 {
     public async Task Handle(InvokeRecActionCommand request, CancellationToken cancel)
     {
-        var http = clientFactory.CreateClient();
+        using var http = clientFactory.CreateClient();
 
         if (request.RestType is null)
         {
@@ -38,9 +36,9 @@ public class InvokeRecActionCommandHandler(
         }
 
         var method = new HttpMethod(request.RestType.ToUpper());
-        var msg = new HttpRequestMessage(method, request.EndpointUri);
+        using var msg = new HttpRequestMessage(method, request.EndpointUri);
 
-        var response = await http.SendAsync(msg, cancel);
+        using var response = await http.SendAsync(msg, cancel);
         var body = await response.Content.ReadAsStringAsync(cancel);
         var headers = response.Headers.ToDictionary();
     }