Refactor activation handling and introduce entity system

Added new `ActivationHandler` class for folder initialization.
Added `ProjectService` class for project-related operations.
Added `Ghost.Entities` project with entity management classes.
Added `EngineEditorWindow` for enhanced user interface.

Changed project files to restructure dependencies and remove unused references.
Changed `ProjectRepository` to use asynchronous methods for improved performance.
Changed data binding in `CreateProjectPage.xaml` and `OpenProjectPage.xaml` to use new data models.
Changed `App.xaml.cs` to utilize the new `ActivationHandler` and include additional services.

Removed `IActivationHandler` interface and integrated its functionality into `ActivationHandler`.
Removed `EditorActivationHandler` as its functionality was merged into `ActivationHandler`.

Updated `AssemblyInfo.cs` to include global using directives for entity types.
Updated image assets to reflect visual resource changes.

Ghost.Editor/ActivationHandler.cs

@@ -0,0 +1,26 @@
+using Ghost.Data.Resources;
+using Microsoft.UI.Xaml;
+using System.IO;
+
+namespace Ghost.Editor;
+
+internal static class ActivationHandler
+{
+    private static void FolderInitialization()
+    {
+        if (!Directory.Exists(DataPath.ApplicationDataFolder))
+        {
+            Directory.CreateDirectory(DataPath.ApplicationDataFolder);
+        }
+
+        if (!Directory.Exists(DataPath.ProjectTemplatesFolder))
+        {
+            Directory.CreateDirectory(DataPath.ProjectTemplatesFolder);
+        }
+    }
+
+    public static void Handle(LaunchActivatedEventArgs args)
+    {
+        FolderInitialization();
+    }
+}