feat(docking): add core enums and base classes

src/Editor/Ghost.Editor/View/Controls/Docking/DockContainer.cs

@@ -0,0 +1,37 @@
+using System.Collections.ObjectModel;
+
+namespace Ghost.Editor.View.Controls.Docking;
+
+public abstract class DockContainer : DockModule
+{
+    public ObservableCollection<DockModule> Children { get; } = new();
+
+    protected DockContainer()
+    {
+        Children.CollectionChanged += OnChildrenChanged;
+    }
+
+    private void OnChildrenChanged(object? sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
+    {
+        if (e.OldItems != null)
+        {
+            foreach (DockModule module in e.OldItems)
+            {
+                module.Owner = null;
+            }
+        }
+
+        if (e.NewItems != null)
+        {
+            foreach (DockModule module in e.NewItems)
+            {
+                module.Owner = this;
+                // module.Root = Root;
+            }
+        }
+        
+        OnChildrenUpdated();
+    }
+    
+    protected virtual void OnChildrenUpdated() { }
+}

src/Editor/Ghost.Editor/View/Controls/Docking/DockModule.cs

@@ -0,0 +1,16 @@
+using Microsoft.UI.Xaml.Controls;
+
+namespace Ghost.Editor.View.Controls.Docking;
+
+public abstract class DockModule : Control
+{
+    public DockContainer? Owner { get; internal set; }
+    // Note: DockingLayout will be implemented in a later task
+    // public DockingLayout? Root { get; internal set; }
+    
+    public void Detach()
+    {
+        // Owner?.Children.Remove(this);
+        Owner = null;
+    }
+}

src/Editor/Ghost.Editor/View/Controls/Docking/Enums.cs

@@ -0,0 +1,10 @@
+namespace Ghost.Editor.View.Controls.Docking;
+
+public enum DockTarget
+{
+    Center,
+    Left,
+    Right,
+    Top,
+    Bottom
+}