Enhance XCUI demo text editing and host bridge

tests/editor/test_window_renderer_api.cpp

@@ -0,0 +1,28 @@
+#include <gtest/gtest.h>
+
+#include "Platform/D3D12WindowRenderer.h"
+
+#include <type_traits>
+
+namespace {
+
+using XCEngine::Editor::Platform::D3D12WindowRenderer;
+using XCEngine::Rendering::RenderSurface;
+
+TEST(D3D12WindowRendererApiTest, ExposesSurfaceAwareRenderCallbackAndAccessor) {
+    using Callback = D3D12WindowRenderer::RenderCallback;
+
+    static_assert(std::is_same_v<
+                  decltype(std::declval<D3D12WindowRenderer&>().GetCurrentRenderSurface()),
+                  const RenderSurface*>);
+    static_assert(std::is_same_v<
+                  decltype(std::declval<D3D12WindowRenderer&>().Render(
+                      std::declval<::XCEngine::Editor::UI::ImGuiBackendBridge&>(),
+                      std::declval<const float*>(),
+                      std::declval<const Callback&>())),
+                  void>);
+
+    SUCCEED();
+}
+
+} // namespace