Split MrtrContext.cs into one class per file

Move MrtrExchange and MrtrContinuation into their own files to follow
the convention of one top-level class per file.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: halter73

src/ModelContextProtocol.Core/Server/MrtrContext.cs

@@ -1,4 +1,3 @@
-using System.Text.Json.Nodes;
 using ModelContextProtocol.Protocol;
 
 namespace ModelContextProtocol.Server;
@@ -55,61 +54,3 @@ public void ResetForNextExchange()
         _exchangeTcs = new TaskCompletionSource<MrtrExchange>(TaskCreationOptions.RunContinuationsAsynchronously);
     }
 }
-
-/// <summary>
-/// Represents a single exchange between the handler and the pipeline during an MRTR flow.
-/// The handler creates the exchange and awaits the response TCS. The pipeline reads the exchange,
-/// sends the <see cref="InputRequest"/> to the client, and completes the TCS when the response arrives.
-/// </summary>
-internal sealed class MrtrExchange
-{
-    public MrtrExchange(string key, InputRequest inputRequest)
-    {
-        Key = key;
-        InputRequest = inputRequest;
-        ResponseTcs = new TaskCompletionSource<InputResponse>(TaskCreationOptions.RunContinuationsAsynchronously);
-    }
-
-    /// <summary>
-    /// The unique key identifying this exchange within the MRTR round trip.
-    /// </summary>
-    public string Key { get; }
-
-    /// <summary>
-    /// The input request that needs to be fulfilled by the client.
-    /// </summary>
-    public InputRequest InputRequest { get; }
-
-    /// <summary>
-    /// The TCS that will be completed with the client's response.
-    /// </summary>
-    public TaskCompletionSource<InputResponse> ResponseTcs { get; }
-}
-
-/// <summary>
-/// Represents a continuation for a suspended MRTR handler, stored between round trips.
-/// </summary>
-internal sealed class MrtrContinuation
-{
-    public MrtrContinuation(Task<JsonNode?> handlerTask, MrtrContext mrtrContext, MrtrExchange pendingExchange)
-    {
-        HandlerTask = handlerTask;
-        MrtrContext = mrtrContext;
-        PendingExchange = pendingExchange;
-    }
-
-    /// <summary>
-    /// The handler task that is suspended awaiting input.
-    /// </summary>
-    public Task<JsonNode?> HandlerTask { get; }
-
-    /// <summary>
-    /// The MRTR context for the handler's async flow.
-    /// </summary>
-    public MrtrContext MrtrContext { get; }
-
-    /// <summary>
-    /// The exchange that is awaiting a response from the client.
-    /// </summary>
-    public MrtrExchange PendingExchange { get; }
-}

src/ModelContextProtocol.Core/Server/MrtrContinuation.cs

@@ -0,0 +1,31 @@
+using System.Text.Json.Nodes;
+
+namespace ModelContextProtocol.Server;
+
+/// <summary>
+/// Represents a continuation for a suspended MRTR handler, stored between round trips.
+/// </summary>
+internal sealed class MrtrContinuation
+{
+    public MrtrContinuation(Task<JsonNode?> handlerTask, MrtrContext mrtrContext, MrtrExchange pendingExchange)
+    {
+        HandlerTask = handlerTask;
+        MrtrContext = mrtrContext;
+        PendingExchange = pendingExchange;
+    }
+
+    /// <summary>
+    /// The handler task that is suspended awaiting input.
+    /// </summary>
+    public Task<JsonNode?> HandlerTask { get; }
+
+    /// <summary>
+    /// The MRTR context for the handler's async flow.
+    /// </summary>
+    public MrtrContext MrtrContext { get; }
+
+    /// <summary>
+    /// The exchange that is awaiting a response from the client.
+    /// </summary>
+    public MrtrExchange PendingExchange { get; }
+}

src/ModelContextProtocol.Core/Server/MrtrExchange.cs

@@ -0,0 +1,33 @@
+using ModelContextProtocol.Protocol;
+
+namespace ModelContextProtocol.Server;
+
+/// <summary>
+/// Represents a single exchange between the handler and the pipeline during an MRTR flow.
+/// The handler creates the exchange and awaits the response TCS. The pipeline reads the exchange,
+/// sends the <see cref="InputRequest"/> to the client, and completes the TCS when the response arrives.
+/// </summary>
+internal sealed class MrtrExchange
+{
+    public MrtrExchange(string key, InputRequest inputRequest)
+    {
+        Key = key;
+        InputRequest = inputRequest;
+        ResponseTcs = new TaskCompletionSource<InputResponse>(TaskCreationOptions.RunContinuationsAsynchronously);
+    }
+
+    /// <summary>
+    /// The unique key identifying this exchange within the MRTR round trip.
+    /// </summary>
+    public string Key { get; }
+
+    /// <summary>
+    /// The input request that needs to be fulfilled by the client.
+    /// </summary>
+    public InputRequest InputRequest { get; }
+
+    /// <summary>
+    /// The TCS that will be completed with the client's response.
+    /// </summary>
+    public TaskCompletionSource<InputResponse> ResponseTcs { get; }
+}