Refactor HTTP response handling and add JSON support

Enhanced `HandleResponseAsync` to return response body as a string and log successful responses. Introduced `JsonOptions` for consistent JSON serialization/deserialization. Added a generic `Deserialize<T>` method for deserializing JSON responses. Updated method signatures to support nullable reference types.

src/ReC.Client/ReCClientHelpers.cs

@@ -5,6 +5,7 @@ using System.Linq;
 using System.Net.Http;
 using System.Net.Http.Json;
 using System.Reflection;
+using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
@@ -73,18 +74,22 @@ namespace ReC.Client
         }
 
         /// <summary>
-        /// Logs the outcome of an HTTP response. Throws a <see cref="ReCApiException"/> when the
+        /// JSON serializer options used when deserializing API responses.
-        /// response indicates a non-success status code; otherwise (optionally) writes an informational
+        /// </summary>
-        /// log entry containing the request and response details.
+        public static readonly JsonSerializerOptions JsonOptions = new JsonSerializerOptions
+        {
+            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
+            PropertyNameCaseInsensitive = true,
+        };
+
+        /// <summary>
+        /// Reads the response body and logs the outcome. Throws a <see cref="ReCApiException"/> when
+        /// the response indicates a non-success status code.
         /// </summary>
-        /// <param name="response">The HTTP response to inspect.</param>
-        /// <param name="logger">An optional logger used to record the outcome. May be <see langword="null"/>.</param>
-        /// <param name="logSuccess">When <see langword="false"/>, successful responses are not logged.</param>
-        /// <param name="cancel">A token to cancel the operation.</param>
 #if NETFRAMEWORK
-        public static async Task HandleResponseAsync(HttpResponseMessage response, ILogger logger = null, bool logSuccess = true, CancellationToken cancel = default)
+        public static async Task<string> HandleResponseAsync(HttpResponseMessage response, ILogger logger = null, bool logSuccess = true, CancellationToken cancel = default)
 #else
-        public static async Task HandleResponseAsync(HttpResponseMessage response, ILogger? logger = null, bool logSuccess = true, CancellationToken cancel = default)
+        public static async Task<string?> HandleResponseAsync(HttpResponseMessage response, ILogger? logger = null, bool logSuccess = true, CancellationToken cancel = default)
 #endif
         {
             var request = response.RequestMessage;
@@ -92,20 +97,6 @@ namespace ReC.Client
             var uri = request?.RequestUri;
             var statusCode = (int)response.StatusCode;
 
-            if (response.IsSuccessStatusCode)
-            {
-                if (logSuccess)
-                {
-                    logger?.LogInformation(
-                        "ReC API request succeeded. {Method} {Uri} -> {StatusCode} ({ReasonPhrase})",
-                        method,
-                        uri,
-                        statusCode,
-                        response.ReasonPhrase);
-                }
-                return;
-            }
-
 #if NETFRAMEWORK
             string body = null;
 #else
@@ -123,15 +114,44 @@ namespace ReC.Client
                 }
                 catch
                 {
-                    // Swallow body read failures; status info is still propagated.
                 }
             }
 
+            if (response.IsSuccessStatusCode)
+            {
+                if (logSuccess)
+                {
+                    logger?.LogInformation(
+                        "ReC API request succeeded. {Method} {Uri} -> {StatusCode} ({ReasonPhrase})",
+                        method,
+                        uri,
+                        statusCode,
+                        response.ReasonPhrase);
+                }
+
+                return body;
+            }
+
             var message = $"ReC API request failed with status {statusCode} ({response.ReasonPhrase}). "
                 + $"{method} {uri}"
                 + (string.IsNullOrWhiteSpace(body) ? string.Empty : $": {body}");
 
             throw new ReCApiException(message, response.StatusCode, response.ReasonPhrase, body, method, uri);
         }
+
+        /// <summary>
+        /// Deserializes a JSON body string into <typeparamref name="T"/>.
+        /// </summary>
+#if NETFRAMEWORK
+        public static T Deserialize<T>(string body)
+#else
+        public static T? Deserialize<T>(string? body)
+#endif
+        {
+            if (string.IsNullOrWhiteSpace(body))
+                return default;
+
+            return JsonSerializer.Deserialize<T>(body, JsonOptions);
+        }
     }
 }