refactor(editor): isolate windowing from composition runtime

editor/app/Bootstrap/Application.cpp

@@ -2,6 +2,7 @@
 #include "EditorResources.h"
 #include "SystemInteractionService.h"
 #include "EditorContext.h"
+#include "EditorShellRuntime.h"
 #include "EditorUtilityWindowRegistry.h"
 #include "EditorWorkspacePanelRegistry.h"
 #include "EditorWindowManager.h"
@@ -156,6 +157,7 @@ bool Application::Initialize(HINSTANCE hInstance, int nCmdShow) {
         *m_resourceService,
         *m_windowHostRuntime,
         App::CreateEditorWorkspacePanelRuntimeSet,
+        App::CreateEditorWorkspaceShellRuntime,
         App::CreateEditorUtilityWindowPanel);
 
     m_editorContext->SetExitRequestHandler([this]() {