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/Services/Contracts/IInspectorService.cs

@@ -0,0 +1,14 @@
+using Ghost.Editor.Contracts;
+
+namespace Ghost.Editor.Services.Contracts;
+
+internal interface IInspectorService
+{
+    public IInspectable? SelectedInspectable
+    {
+        get;
+        set;
+    }
+
+    public event Action? OnSelectionChanged;
+}

Ghost.App/Services/Contracts/INotificationService.cs

@@ -0,0 +1,8 @@
+using Ghost.Editor.Models;
+
+namespace Ghost.Editor.Services.Contracts;
+
+public interface INotificationService
+{
+    public void ShowNotification(string? message, MessageType type, int duration = 5, string? title = null);
+}

Ghost.App/Services/Contracts/IProgressService.cs

@@ -0,0 +1,9 @@
+namespace Ghost.Editor.Services.Contracts;
+
+public interface IProgressService
+{
+    public void ShowProgress(string message, double progress = 0.0);
+    public void ShowIndeterminateProgress(string message);
+    public void SetProgress(double progress);
+    public void HideProgress();
+}

Ghost.App/Services/InspectorService.cs

@@ -0,0 +1,22 @@
+using Ghost.Editor.Contracts;
+using Ghost.Editor.Services.Contracts;
+
+namespace Ghost.Editor.Services;
+
+public class InspectorService : IInspectorService
+{
+    public IInspectable? SelectedInspectable
+    {
+        get => field;
+        set
+        {
+            if (field != value)
+            {
+                field = value;
+                OnSelectionChanged?.Invoke();
+            }
+        }
+    }
+
+    public event Action? OnSelectionChanged;
+}

Ghost.App/Services/NotificationService.cs

@@ -4,7 +4,7 @@ using Ghost.Editor.Services.Contracts;
 using Microsoft.UI.Xaml.Controls;
 using System;
 
-namespace Ghost.App.Services;
+namespace Ghost.Editor.Services;
 
 public class NotificationService : INotificationService
 {

Ghost.App/Services/ProgressService.cs

@@ -4,7 +4,7 @@ using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
 using System.Runtime.CompilerServices;
 
-namespace Ghost.App.Services;
+namespace Ghost.Editor.Services;
 
 public class ProgressService : IProgressService
 {