Clean up namespaces (#410)

No meaningful code changes, just lots of namespace shuffling to have fewer namespaces and to put things in better namespaces.

src/ModelContextProtocol/Protocol/JsonRpcResponse.cs

@@ -0,0 +1,29 @@
+using System.Text.Json.Nodes;
+using System.Text.Json.Serialization;
+
+namespace ModelContextProtocol.Protocol;
+
+/// <summary>
+/// A successful response message in the JSON-RPC protocol.
+/// </summary>
+/// <remarks>
+/// <para>
+/// Response messages are sent in reply to a request message and contain the result of the method execution.
+/// Each response includes the same ID as the original request, allowing the sender to match responses
+/// with their corresponding requests.
+/// </para>
+/// <para>
+/// This class represents a successful response with a result. For error responses, see <see cref="JsonRpcError"/>.
+/// </para>
+/// </remarks>
+public class JsonRpcResponse : JsonRpcMessageWithId
+{
+    /// <summary>
+    /// Gets the result of the method invocation.
+    /// </summary>
+    /// <remarks>
+    /// This property contains the result data returned by the server in response to the JSON-RPC method request.
+    /// </remarks>
+    [JsonPropertyName("result")]
+    public required JsonNode? Result { get; init; }
+}