Add support for data to McpProtocolException (#1028)

tests/ModelContextProtocol.Tests/PlatformDetection.cs

@@ -6,4 +6,13 @@ internal static class PlatformDetection
 {
     public static bool IsMonoRuntime { get; } = Type.GetType("Mono.Runtime") is not null;
     public static bool IsWindows { get; } = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
+
+    // On .NET Framework, Exception.Data requires values to be serializable with [Serializable].
+    // JsonElement is not marked as serializable, so certain features are not available on that platform.
+    public static bool IsNetFramework { get; } =
+#if NET
+        false;
+#else
+        true;
+#endif
 }