checkpoint(new_editor): native d3d12 ui path

Key node 1: move main-window UI presentation onto the D3D12 render loop with native UI renderer, text system, and texture host.

Key node 2: wire frame timing/FPS display, window runtime, swapchain presentation, and native screenshot capture around the new path.

Key node 3: carry editor shell/workspace/viewport/panel interaction updates needed by the new renderer and detached window flow.

Key node 4: pump async resource loads and scene bridge follow-up needed for scene content visibility in new_editor.

new_editor/app/Features/Project/ProjectBrowserModel.cpp

@@ -1,5 +1,6 @@
 #include "ProjectBrowserModel.h"
 #include <filesystem>
+#include <XCEditor/Foundation/UIEditorRuntimeTrace.h>
 #include <string>
 #include <string_view>
 #include <vector>
@@ -89,6 +90,10 @@ std::u8string BuildU8String(std::string_view value) {
     return result;
 }
 
+void TraceProjectBrowser(std::string message) {
+    ::XCEngine::UI::Editor::AppendUIEditorRuntimeTrace("startup", std::move(message));
+}
+
 } // namespace
 
 std::string ToLowerCopy(std::string value) {
@@ -550,14 +555,31 @@ std::string RemapMovedItemId(
 
 void ProjectBrowserModel::Initialize(const std::filesystem::path& repoRoot) {
     m_assetsRootPath = (repoRoot / "project/Assets").lexically_normal();
+    TraceProjectBrowser("ProjectBrowserModel::Initialize assetsRoot=" + PathToUtf8String(m_assetsRootPath));
     std::error_code errorCode = {};
     if (!std::filesystem::exists(m_assetsRootPath, errorCode)) {
         std::filesystem::create_directories(m_assetsRootPath / "Scenes", errorCode);
     }
+    if (errorCode) {
+        TraceProjectBrowser("ProjectBrowserModel::Initialize filesystem error=" + errorCode.message());
+    }
     Refresh();
+    TraceProjectBrowser(
+        "ProjectBrowserModel::Initialize complete folders=" +
+        std::to_string(m_folderEntries.size()) +
+        " assets=" +
+        std::to_string(m_assetEntries.size()));
 }
 
 void ProjectBrowserModel::SetFolderIcon(const ::XCEngine::UI::UITextureHandle& icon) {
+    if (m_folderIcon.nativeHandle == icon.nativeHandle &&
+        m_folderIcon.width == icon.width &&
+        m_folderIcon.height == icon.height &&
+        m_folderIcon.kind == icon.kind &&
+        m_folderIcon.resourceHandle == icon.resourceHandle) {
+        return;
+    }
+
     m_folderIcon = icon;
     if (!m_assetsRootPath.empty()) {
         RefreshFolderTree();
@@ -565,9 +587,17 @@ void ProjectBrowserModel::SetFolderIcon(const ::XCEngine::UI::UITextureHandle& i
 }
 
 void ProjectBrowserModel::Refresh() {
+    TraceProjectBrowser("ProjectBrowserModel::Refresh begin");
     RefreshFolderTree();
     EnsureValidCurrentFolder();
     RefreshAssetList();
+    TraceProjectBrowser(
+        "ProjectBrowserModel::Refresh end currentFolder=" +
+        m_currentFolderId +
+        " folders=" +
+        std::to_string(m_folderEntries.size()) +
+        " assets=" +
+        std::to_string(m_assetEntries.size()));
 }
 
 bool ProjectBrowserModel::Empty() const {
@@ -1186,6 +1216,7 @@ namespace XCEngine::UI::Editor::App {
 
 
 void ProjectBrowserModel::RefreshAssetList() {
+    TraceProjectBrowser("ProjectBrowserModel::RefreshAssetList begin");
     EnsureValidCurrentFolder();
 
     m_assetEntries.clear();
@@ -1239,6 +1270,12 @@ void ProjectBrowserModel::RefreshAssetList() {
             CanPreviewItem(entry.path(), assetEntry.kind, assetEntry.directory);
         m_assetEntries.push_back(std::move(assetEntry));
     }
+
+    TraceProjectBrowser(
+        "ProjectBrowserModel::RefreshAssetList end currentFolder=" +
+        m_currentFolderId +
+        " assets=" +
+        std::to_string(m_assetEntries.size()));
 }
 
 } // namespace XCEngine::UI::Editor::App
@@ -1247,6 +1284,7 @@ namespace XCEngine::UI::Editor::App {
 
 
 void ProjectBrowserModel::RefreshFolderTree() {
+    TraceProjectBrowser("ProjectBrowserModel::RefreshFolderTree begin");
     m_folderEntries.clear();
     m_treeItems.clear();
 
@@ -1280,6 +1318,9 @@ void ProjectBrowserModel::RefreshFolderTree() {
     };
 
     appendFolderRecursive(appendFolderRecursive, m_assetsRootPath, 0u);
+    TraceProjectBrowser(
+        "ProjectBrowserModel::RefreshFolderTree end folders=" +
+        std::to_string(m_folderEntries.size()));
 }
 
 std::vector<std::string> ProjectBrowserModel::CollectCurrentFolderAncestorIds() const {