Refactor project structure and enhance functionality

Added `InternalsVisibleTo` attribute for "Ghost.Editor" in `AssemblyInfo.cs`.
Added a binary file `Empty.zip` to the project.
Added a new `ProjectMetadata` class in `ProjectMetadata.cs`.
Added new states and interfaces for managing application states in `EditorState.cs`, `LandingState.cs`, and `IAppState.cs`.
Added a notification service in `INotificationService.cs` and `StackedNotificationService.cs`.
Added new XAML files for UI components, including `InspectorView.xaml` and `InternalControls.xaml`.

Changed the `ProjectInfo` class in `ProjectInfo.cs` to include a `MetadataPath` property instead of `Path` and `EngineVersion`.
Changed the `TemplateInfo` class in `TemplateInfo.cs` to use a struct instead of a class for `TemplateData`.
Changed the `ProjectService` class to use the new `ProjectRepository` for managing project data.

Removed several using directives and the entire `ProjectRepository` class from `ProjectRepository.cs`, replacing it with a new implementation.
Removed old methods and properties in `EntityManager` and `World` classes to improve entity management and component handling.

Updated the `Ghost.Data.csproj` file to include the new `Empty.zip` file as a content item.
Updated the `ProjectRepository` class to manage project data using SQLite.
Updated various XAML files to include new styles and controls, improving the overall UI design.
Updated the `CreateProjectViewModel` to include a notification service and handle project creation logic.
Updated the test project to include references to the new `Ghost.Graphics` project and modified test cases to align with the new structure.

Ghost.Editor/ViewModel/Pages/EngineEditor/ProjectViewModel.cs

@@ -0,0 +1,5 @@
+namespace Ghost.Editor.ViewModel.Pages.EngineEditor;
+
+internal class ProjectViewModel
+{
+}

Ghost.Editor/ViewModel/Pages/Landing/CreateProjectViewModel.cs

@@ -2,18 +2,20 @@
 using CommunityToolkit.Mvvm.Input;
 using Ghost.Data.Models;
 using Ghost.Data.Services;
+using Ghost.Editor.AppStates;
 using Ghost.Editor.Contracts;
 using Ghost.Editor.Helpers;
-using Ghost.Editor.View.Windows;
+using Ghost.Editor.Services;
+using Ghost.Engine.Resources;
+using Microsoft.UI.Xaml.Controls;
 using System.Collections.ObjectModel;
 using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
-using Windows.ApplicationModel;
 
 namespace Ghost.Editor.ViewModel.Pages.Landing;
 
-internal partial class CreateProjectViewModel(ProjectService projectService) : ObservableRecipient, INavigationAware
+internal partial class CreateProjectViewModel(StackedNotificationService notificationService, ProjectService projectService, AppStateService stateService) : ObservableRecipient, INavigationAware
 {
     public ObservableCollection<TemplateData> templates = new();
 
@@ -25,14 +27,14 @@ internal partial class CreateProjectViewModel(ProjectService projectService) : O
     }
 
     [ObservableProperty]
-    public partial string ProjectName
+    public partial string? ProjectName
     {
         get;
         set;
     }
 
     [ObservableProperty]
-    public partial string ProjectLocation
+    public partial string? ProjectLocation
     {
         get;
         set;
@@ -40,7 +42,8 @@ internal partial class CreateProjectViewModel(ProjectService projectService) : O
 
     public async void OnNavigatedTo(object? parameter)
     {
-        await foreach (var (path, info) in projectService.GetProjectTemplatesAsync())
+        templates.Clear();
+        await foreach (var (path, info) in ProjectService.GetProjectTemplatesAsync())
         {
             templates.Add(new(path, info));
         }
@@ -55,25 +58,39 @@ internal partial class CreateProjectViewModel(ProjectService projectService) : O
     [RelayCommand]
     private async Task SelectionProjectLocation()
     {
-        ProjectLocation = (await SystemUtilities.OpenFolderPickerAsync())?.Path ?? string.Empty;
+        var folder = await SystemUtilities.OpenFolderPickerAsync();
+        if (folder != null)
+        {
+            ProjectLocation = folder.Path;
+        }
     }
 
     [RelayCommand]
     private async Task CreateProject()
     {
-        if (string.IsNullOrWhiteSpace(ProjectName) || !Directory.Exists(ProjectLocation) || SelectedTemplate == null)
+        if (string.IsNullOrWhiteSpace(ProjectName)
+            || !Directory.Exists(ProjectLocation)
+            || !SelectedTemplate.HasValue)
         {
+            notificationService.ShowNotification("Incorrect project info", InfoBarSeverity.Error);
             return;
         }
 
-        var projectPath = await projectService.CreateProjectAsync(ProjectName, ProjectLocation, SelectedTemplate.directory);
-
-        var packageVersion = Package.Current.Id.Version;
-        var newProject = await projectService.AddProjectAsync(ProjectName, projectPath, new System.Version(packageVersion.Major, packageVersion.Minor, packageVersion.Build));
-
-        if (EngineEditorWindow.TryLoadProject(newProject))
+        var result = await projectService.CreateProjectAsync(ProjectName, ProjectLocation, EngineData.s_engineVersion, SelectedTemplate.Value.directory);
+        if (!result.success || result.data == null)
         {
-            App.GetService<LandingWindow>().Close();
+            notificationService.ShowNotification(result.message, InfoBarSeverity.Error);
+            return;
+        }
+
+        var metadata = await ProjectService.LoadMetadataAsync(result.data.MetadataPath); // Metadata should not be null here if create project succeeded
+        try
+        {
+            await stateService.TransitionToAsync(StateKey.EngineEditor, metadata);
+        }
+        catch (System.Exception e)
+        {
+            notificationService.ShowNotification($"Failed to load project: {e.Message}", InfoBarSeverity.Error);
         }
     }
 }