refactor(new_editor/app): reorganize host structure and add smoke test

new_editor/app/Rendering/D3D12/D3D12WindowSwapChainPresenterPresentation.cpp

@@ -0,0 +1,50 @@
+#include "D3D12WindowSwapChainPresenter.h"
+
+#include <sstream>
+
+namespace XCEngine::UI::Editor::Host {
+
+bool D3D12WindowSwapChainPresenter::PreparePresentSurface(
+    const ::XCEngine::Rendering::RenderContext& renderContext) {
+    if (!renderContext.IsValid() || renderContext.commandList == nullptr) {
+        m_lastError = "PreparePresentSurface requires a valid render context.";
+        return false;
+    }
+
+    if (m_swapChain == nullptr) {
+        m_lastError = "PreparePresentSurface requires an initialized swap chain.";
+        return false;
+    }
+
+    const std::uint32_t backBufferIndex = m_swapChain->GetCurrentBackBufferIndex();
+    if (backBufferIndex >= m_backBufferViews.size() ||
+        m_backBufferViews[backBufferIndex] == nullptr) {
+        std::ostringstream error = {};
+        error << "PreparePresentSurface could not find the current swap chain RTV. index="
+              << backBufferIndex
+              << " rtvCount="
+              << m_backBufferViews.size();
+        m_lastError = error.str();
+        return false;
+    }
+
+    renderContext.commandList->TransitionBarrier(
+        m_backBufferViews[backBufferIndex],
+        ::XCEngine::RHI::ResourceStates::Present,
+        ::XCEngine::RHI::ResourceStates::RenderTarget);
+    m_lastError.clear();
+    return true;
+}
+
+bool D3D12WindowSwapChainPresenter::PresentFrame() {
+    if (m_swapChain == nullptr) {
+        m_lastError = "PresentFrame requires an initialized swap chain.";
+        return false;
+    }
+
+    m_swapChain->Present(0, 0);
+    m_lastError.clear();
+    return true;
+}
+
+} // namespace XCEngine::UI::Editor::Host