Refactor project from Ghost.App to Ghost.Editor

Changed the project structure to reflect a shift from `Ghost.App` to `Ghost.Editor`, updating namespaces and class names throughout.

Changed the application class in `App.xaml` and `App.xaml.cs` from `GhostApplication` to `EditorApplication`.

Changed several service interfaces to reside under `Ghost.Editor.Services.Contracts`, including `IInspectorService`, `INotificationService`, and `IProgressService`.

Added `InspectorView` and `InspectorViewModel` classes to manage inspector functionality.

Added `NavigationTabView` and `NavigationTabPage` classes to facilitate navigation within the editor.

Enhanced `WorldNode` and `EntityNode` classes to support scene graph functionality, including serialization and entity management.

Updated the project file `Ghost.Editor.csproj` to reflect the new structure and removed old references.

Modified the solution file `GhostEngine.sln` to remove references to `Ghost.App` and include `Ghost.Editor`.

Updated unit tests to align with the new namespaces and project structure.

Ghost.App/Core/SceneGraph/WorldNode.cs

@@ -0,0 +1,195 @@
+using Ghost.Editor.Contracts;
+using Ghost.Editor.Core.AssetHandle;
+using Ghost.Editor.Core.Serializer;
+using Ghost.Editor.Resources;
+using Ghost.Engine.Components;
+using Ghost.Entities;
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+using System.Text.Json.Serialization;
+
+namespace Ghost.Editor.Core.SceneGraph;
+
+[JsonConverter(typeof(WorldNodeSerializer))]
+public partial class WorldNode : SceneGraphNode, IEquatable<WorldNode>
+{
+    private World _world;
+    private Dictionary<Entity, EntityNode> _entityNodeLookup = new();
+
+    public World World => _world;
+    public Dictionary<Entity, EntityNode> EntityNodeLookup => _entityNodeLookup;
+
+    public override SceneGraphNodeType NodeType => SceneGraphNodeType.Scene;
+
+    public WorldNode(World world, string name)
+    {
+        _world = world;
+        Name = name;
+    }
+
+    internal WorldNode()
+    {
+        _world = World.Create();
+    }
+
+    private void UpdateLookup(Entity key, EntityNode value)
+    {
+        _entityNodeLookup[key] = value;
+        if (value.Children == null)
+        {
+            return;
+        }
+
+        foreach (var child in value.Children)
+        {
+            if (child is EntityNode entityChild)
+            {
+                UpdateLookup(entityChild.Entity, entityChild);
+            }
+        }
+    }
+
+    public override void AddChild(SceneGraphNode child)
+    {
+        if (child is not EntityNode entityNode)
+        {
+            throw new ArgumentException("Child must be of type EntityNode.", nameof(child));
+        }
+
+        base.AddChild(entityNode);
+        UpdateLookup(entityNode.Entity, entityNode);
+    }
+
+    public override bool RemoveChild(SceneGraphNode child)
+    {
+        if (child is not EntityNode entityNode)
+        {
+            throw new ArgumentException("Child must be of type EntityNode.", nameof(child));
+        }
+
+        var result = base.RemoveChild(child);
+        if (result)
+        {
+            _entityNodeLookup.Remove(entityNode.Entity);
+        }
+
+        return result;
+    }
+
+    private EntityNode BuildNodeRecursive(Entity entity, World world)
+    {
+        if (!_entityNodeLookup.TryGetValue(entity, out var node))
+        {
+            node = new EntityNode(entity, "New Entity");
+            _entityNodeLookup[entity] = node;
+        }
+
+        var hc = world.EntityManager.GetComponent<Hierarchy>(entity);
+        var child = hc.ValueRO.firstChild;
+
+        while (child != Entity.Invalid)
+        {
+            node.AddChild(BuildNodeRecursive(child, world));
+            var childHC = world.EntityManager.GetComponent<Hierarchy>(child);
+            child = childHC.ValueRO.nextSibling;
+        }
+
+        return node;
+    }
+
+    private void BuildGraph()
+    {
+        foreach (var (entity, hierarchy) in _world.Query<Hierarchy>())
+        {
+            if (hierarchy.ValueRO.parent == Entity.Invalid)
+            {
+                var node = BuildNodeRecursive(entity, _world);
+                AddChild(node);
+            }
+        }
+    }
+
+    public Task LoadAsync()
+    {
+        return Task.Run(BuildGraph);
+    }
+
+    public void Unload()
+    {
+        _world.Dispose();
+        _world = null!;
+
+        Children?.Clear();
+        _entityNodeLookup.Clear();
+    }
+
+    public override string ToString()
+    {
+        return $"WorldNode: {Name} (World ID: {_world.ID})";
+    }
+
+    public override int GetHashCode()
+    {
+        return HashCode.Combine(_world, Name);
+    }
+
+    public override bool Equals(object? obj)
+    {
+        return obj is WorldNode other && Equals(other);
+    }
+
+    public bool Equals(WorldNode? other)
+    {
+        if (other is null)
+        {
+            return false;
+        }
+
+        if (ReferenceEquals(this, other))
+        {
+            return true;
+        }
+
+        return _world.Equals(other._world) && Name == other.Name;
+    }
+
+    public static bool operator ==(WorldNode? left, WorldNode? right)
+    {
+        if (left is null)
+        {
+            return right is null;
+        }
+        return left.Equals(right);
+    }
+
+    public static bool operator !=(WorldNode? left, WorldNode? right)
+    {
+        return !(left == right);
+    }
+}
+
+public partial class WorldNode : IInspectable
+{
+    public IconSource? Icon => EditorIconSource.scene_24;
+
+    [AssetOpenHandler(FileExtensions.SCENE_FILE_EXTENSION)]
+    public static async void Open(string path)
+    {
+        await EditorWorldManager.LoadWorld(path);
+    }
+
+    public UIElement? HeaderContent()
+    {
+        return new TextBlock
+        {
+            Text = Name,
+            Style = Application.Current.Resources["SubtitleTextBlockStyle"] as Style,
+            VerticalAlignment = VerticalAlignment.Center
+        };
+    }
+
+    public UIElement? InspectorContent()
+    {
+        return null;
+    }
+}