Add missing enum serialization configuration.

Author: eiriktsarpalis

src/ModelContextProtocol/Protocol/Types/ContextInclusion.cs

@@ -1,23 +1,29 @@
-namespace ModelContextProtocol.Protocol.Types;
+using System.Text.Json.Serialization;
+
+namespace ModelContextProtocol.Protocol.Types;
 
 /// <summary>
 /// A request to include context from one or more MCP servers (including the caller), to be attached to the prompt.
 /// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
 /// </summary>
+[JsonConverter(typeof(JsonStringEnumConverter<ContextInclusion>))]
 public enum ContextInclusion
 {
     /// <summary>
     /// No context should be included.
     /// </summary>
+    [JsonStringEnumMemberName("none")]
     None,
 
     /// <summary>
     /// Include context from the server that sent the request.
     /// </summary>
+    [JsonStringEnumMemberName("thisServer")]
     ThisServer,
 
     /// <summary>
     /// Include context from all servers that the client is connected to.
     /// </summary>
+    [JsonStringEnumMemberName("allServers")]
     AllServers
 }

src/ModelContextProtocol/Protocol/Types/LoggingLevel.cs

@@ -7,6 +7,7 @@ namespace ModelContextProtocol.Protocol.Types;
 /// These map to syslog message severities, as specified in RFC-5424:
 /// https://datatracker.ietf.org/doc/html/rfc5424#section-6.2.1
 /// </summary>
+[JsonConverter(typeof(JsonStringEnumConverter<LoggingLevel>))]
 public enum LoggingLevel
 {
     /// <summary>Detailed debug information, typically only valuable to developers.</summary>

src/ModelContextProtocol/Protocol/Types/Role.cs

@@ -6,6 +6,7 @@ namespace ModelContextProtocol.Protocol.Types;
 /// Represents the type of role in the conversation.
 /// <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.json">See the schema for details</see>
 /// </summary>
+[JsonConverter(typeof(JsonStringEnumConverter<Role>))]
 public enum Role
 {
     /// <summary>