feat: add editor viewport host service

editor/src/Application.h

@@ -3,6 +3,7 @@
 #include "Platform/D3D12WindowRenderer.h"
 #include "UI/ImGuiBackendBridge.h"
 #include "UI/ImGuiSession.h"
+#include "Viewport/ViewportHostService.h"
 
 #include <XCEngine/Rendering/RenderContext.h>
 #include <memory>
@@ -35,6 +36,7 @@ public:
     Rendering::RenderContext GetMainRenderContext() const { return m_windowRenderer.GetRenderContext(); }
     RHI::RHIDevice* GetMainRHIDevice() const { return m_windowRenderer.GetRHIDevice(); }
     RHI::RHISwapChain* GetMainSwapChain() const { return m_windowRenderer.GetSwapChain(); }
+    IViewportHostService& GetViewportHostService() { return m_viewportHostService; }
     bool IsRenderReady() const { return m_renderReady; }
     HWND GetWindowHandle() const { return m_hwnd; }
     
@@ -60,6 +62,7 @@ private:
     Platform::D3D12WindowRenderer m_windowRenderer;
     UI::ImGuiBackendBridge m_imguiBackend;
     UI::ImGuiSession m_imguiSession;
+    ViewportHostService m_viewportHostService;
     uint64_t m_exitRequestedHandlerId = 0;
     std::wstring m_lastWindowTitle;
     bool m_renderReady = false;