Add project files.

Core.Blueprint.External/TrackingMechanismExtension.cs

@@ -0,0 +1,18 @@
+using Microsoft.AspNetCore.Http;
+
+namespace Core.Blueprint.External
+{
+    public sealed class TrackingMechanismExtension(IHttpContextAccessor httpContextAccessor) : DelegatingHandler
+    {
+        private readonly IHttpContextAccessor _httpContextAccessor = httpContextAccessor ?? throw new ArgumentNullException(nameof(httpContextAccessor));
+
+        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            if (_httpContextAccessor.HttpContext != null)
+            {
+                request.Headers.Add("TrackingId", Guid.NewGuid().ToString());
+            }
+            return await base.SendAsync(request, cancellationToken).ConfigureAwait(false);
+        }
+    }
+}