Remove stale 'Deferred Task Creation with MRTR' section from tasks.md to fix docfx warnings

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

Author: halter73

docs/concepts/tasks/tasks.md

@@ -137,58 +137,6 @@ Task support levels:
 - `Optional` (default for async methods): Tool can be called with or without task augmentation
 - `Required`: Tool must be called with task augmentation
 
-### Deferred Task Creation with MRTR
-
-<!-- mlc-disable-next-line -->
-> [!WARNING]
-> Deferred task creation depends on both the [Tasks](xref:tasks) and [MRTR](xref:mrtr) experimental features.
-
-By default, when a client sends task metadata with a `tools/call` request, the SDK creates a task immediately and runs the tool in the background. **Deferred task creation** delays the task creation, letting the tool perform ephemeral [MRTR](xref:mrtr) exchanges first — for example, to confirm an action with the user or gather required parameters — before committing to a background task.
-
-To opt in, set `DeferTaskCreation = true` on the tool:
-
-```csharp
-McpServerTool.Create(
-    async (string vmName, McpServer server, CancellationToken ct) =>
-    {
-        // Ephemeral MRTR — uses incomplete result / retry cycle.
-        var confirmation = await server.ElicitAsync(new ElicitRequestParams
-        {
-            Message = $"Provision VM '{vmName}'? This will incur costs.",
-            RequestedSchema = new()
-        }, ct);
-
-        if (confirmation.Action != "confirm")
-        {
-            return "Cancelled by user.";
-        }
-
-        // Transition to a background task.
-        await server.CreateTaskAsync(ct);
-
-        // Background work — runs as a task, client polls for status.
-        await Task.Delay(TimeSpan.FromMinutes(5), ct);
-        return $"VM '{vmName}' provisioned successfully.";
-    },
-    new McpServerToolCreateOptions
-    {
-        Name = "provision-vm",
-        Description = "Provisions a VM with user confirmation",
-        DeferTaskCreation = true,
-        Execution = new ToolExecution { TaskSupport = ToolTaskSupport.Optional },
-    })
-```
-
-After <xref:ModelContextProtocol.Server.McpServer.CreateTaskAsync*> returns:
-
-- The MRTR phase ends. The client receives a `CreateTaskResult` with the `taskId`.
-- Any subsequent `ElicitAsync` or `SampleAsync` calls in the handler use the task's `input_required` / `tasks/input_response` workflow instead of MRTR.
-- The handler's cancellation token is re-linked to the task's lifecycle (TTL expiration, explicit `tasks/cancel`).
-
-If the tool returns without calling `CreateTaskAsync`, a normal (non-task) result is sent to the client — no task is created.
-
-For more details on the MRTR mechanism and the transition flow, see [Transitioning from MRTR to Tasks](xref:mrtr#transitioning-from-mrtr-to-tasks).
-
 ### Explicit Task Creation with `IMcpTaskStore`
 
 For more control over task lifecycle, tools can directly interact with <xref:ModelContextProtocol.IMcpTaskStore> and return an `McpTask`. This approach allows you to: