.NET: Improve Todo multithreading and inject todos into message list (#5655)

* Improve Todo multithreading and inject todos into message list

* Address PR comments

dotnet/samples/02-agents/Harness/Harness_Shared_Console/Commands/ICommandHandler.cs

@@ -24,5 +24,5 @@ public interface ICommandHandler
     /// <param name="input">The raw user input string.</param>
     /// <param name="session">The current agent session.</param>
     /// <returns><see langword="true"/> if this handler handled the input; <see langword="false"/> otherwise.</returns>
-    bool TryHandle(string input, AgentSession session);
+    ValueTask<bool> TryHandleAsync(string input, AgentSession session);
 }

dotnet/samples/02-agents/Harness/Harness_Shared_Console/Commands/ModeCommandHandler.cs

@@ -27,17 +27,17 @@ internal sealed class ModeCommandHandler : ICommandHandler
     public string? GetHelpText() => this._modeProvider is not null ? "/mode [plan|execute] (show or switch mode)" : null;
 
     /// <inheritdoc/>
-    public bool TryHandle(string input, AgentSession session)
+    public ValueTask<bool> TryHandleAsync(string input, AgentSession session)
     {
         if (!input.StartsWith("/mode ", StringComparison.OrdinalIgnoreCase) && !input.Equals("/mode", StringComparison.OrdinalIgnoreCase))
         {
-            return false;
+            return ValueTask.FromResult(false);
         }
 
         if (this._modeProvider is null)
         {
             System.Console.WriteLine("AgentModeProvider is not available.");
-            return true;
+            return ValueTask.FromResult(true);
         }
 
         string[] parts = input.Split(' ', 2, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
@@ -45,7 +45,7 @@ internal sealed class ModeCommandHandler : ICommandHandler
         {
             string current = this._modeProvider.GetMode(session);
             System.Console.WriteLine($"\n  Current mode: {current}\n");
-            return true;
+            return ValueTask.FromResult(true);
         }
 
         string newMode = parts[1];
@@ -64,6 +64,6 @@ internal sealed class ModeCommandHandler : ICommandHandler
             System.Console.ResetColor();
         }
 
-        return true;
+        return ValueTask.FromResult(true);
     }
 }

dotnet/samples/02-agents/Harness/Harness_Shared_Console/Commands/TodoCommandHandler.cs

@@ -24,7 +24,7 @@ internal sealed class TodoCommandHandler : ICommandHandler
     public string? GetHelpText() => this._todoProvider is not null ? "/todos (show todo list)" : null;
 
     /// <inheritdoc/>
-    public bool TryHandle(string input, AgentSession session)
+    public async ValueTask<bool> TryHandleAsync(string input, AgentSession session)
     {
         if (!input.Equals("/todos", StringComparison.OrdinalIgnoreCase))
         {
@@ -37,7 +37,7 @@ internal sealed class TodoCommandHandler : ICommandHandler
             return true;
         }
 
-        var todos = this._todoProvider.GetAllTodos(session);
+        var todos = await this._todoProvider.GetAllTodosAsync(session).ConfigureAwait(false);
         if (todos.Count == 0)
         {
             System.Console.WriteLine("\n  No todos yet.\n");

dotnet/samples/02-agents/Harness/Harness_Shared_Console/HarnessConsole.cs

@@ -69,7 +69,7 @@ public static class HarnessConsole
             bool handled = false;
             foreach (var handler in commandHandlers)
             {
-                if (handler.TryHandle(userInput, session))
+                if (await handler.TryHandleAsync(userInput, session).ConfigureAwait(false))
                 {
                     handled = true;
                     break;