Ensure containers show up in the menu when they are created

Toolkit.Foundation/Activated.cs

@@ -1,3 +1,10 @@
 namespace Toolkit.Foundation;
 
-public record Activated;
+public record Activated<TValue>(TValue? Value = default);
+
+public record Activated
+{
+    public static Activated<TValue> As<TValue>(TValue value) => new(value);
+
+    public static Activated<TValue> As<TValue>() where TValue : new() => new(new TValue());
+}

Toolkit.Foundation/ConfigurationInitializer.cs

@@ -20,6 +20,6 @@ public class ConfigurationInitializer<TConfiguration>(IConfigurationReader<TConf
             }
         }
 
-        await publisher.PublishUI(new Changed<TConfiguration>(configuration));
+        await publisher.PublishUI(new Activated<TConfiguration>(configuration));
     }
 }

Toolkit.Foundation/IValueStore.cs

@@ -1,6 +1,6 @@
 namespace Toolkit.Foundation;
 
-public interface IContainer<T>
+public interface IValueStore<T>
 {
     T? Value { get; }
 

Toolkit.Foundation/ObservableViewModel.cs

@@ -92,12 +92,13 @@ public partial class ObservableViewModel<TKey, TValue>(IServiceProvider provider
     IMediator mediator,
     IPublisher publisher,
     ISubscriber subscriber,
-    IDisposer disposer) : ObservableViewModel(provider, factory, mediator, publisher, subscriber, disposer)
-    where TValue : notnull
+    IDisposer disposer,
+    TValue? value = null) : ObservableViewModel(provider, factory, mediator, publisher, subscriber, disposer)
+    where TValue : class
 {
     [ObservableProperty]
     private TKey? key;
 
     [ObservableProperty]
-    private TValue? value;
+    private TValue? value = value;
 }

Toolkit.Foundation/ValueStore.cs

@@ -1,7 +1,7 @@
 namespace Toolkit.Foundation;
 
-public class Container<T> :
-    IContainer<T>
+public class ValueStore<T> :
+    IValueStore<T>
 {
     public T? Value { get; private set; }
 

Toolkit.UI.Controls.Avalonia/Class1.cs

@@ -0,0 +1,17 @@
+using Avalonia.Controls;
+using Avalonia.Controls.Primitives;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Toolkit.UI.Controls;
+
+public class AttachedFlyout : PopupFlyoutBase
+{
+    protected override Control CreatePresenter()
+    {
+        throw new NotImplementedException();
+    }
+}