Fixed error messages for provider requests (#778)

app/MindWork AI Studio/Provider/ProviderRequestException.cs

@@ -0,0 +1,25 @@
+using System.Net;
+
+namespace AIStudio.Provider;
+
+public sealed class ProviderRequestException(
+    ProviderRequestFailureReason failureReason,
+    string userMessage,
+    HttpStatusCode? statusCode = null,
+    string reasonPhrase = "",
+    string responseBody = "") : Exception(userMessage)
+{
+    public ProviderRequestException() : this(ProviderRequestFailureReason.NONE, string.Empty)
+    {
+    }
+
+    public ProviderRequestFailureReason FailureReason { get; } = failureReason;
+
+    public string UserMessage { get; } = userMessage;
+
+    public HttpStatusCode? StatusCode { get; } = statusCode;
+
+    public string ReasonPhrase { get; } = reasonPhrase;
+
+    public string ResponseBody { get; } = responseBody;
+}