refactor(new_editor): streamline internal layout and command routing

new_editor/src/Workspace/WorkspaceModelValidation.cpp

@@ -0,0 +1,28 @@
+#include "Workspace/WorkspaceModelInternal.h"
+
+namespace XCEngine::UI::Editor {
+
+UIEditorWorkspaceValidationResult ValidateUIEditorWorkspace(
+    const UIEditorWorkspaceModel& workspace) {
+    std::unordered_set<std::string> panelIds = {};
+    UIEditorWorkspaceValidationResult result =
+        Internal::ValidateNodeRecursive(workspace.root, panelIds);
+    if (!result.IsValid()) {
+        return result;
+    }
+
+    if (!workspace.activePanelId.empty()) {
+        const UIEditorWorkspacePanelState* activePanel =
+            FindUIEditorWorkspaceActivePanel(workspace);
+        if (activePanel == nullptr) {
+            return Internal::MakeValidationError(
+                UIEditorWorkspaceValidationCode::InvalidActivePanelId,
+                "Active panel id '" + workspace.activePanelId +
+                    "' is missing or hidden by the current tab selection.");
+        }
+    }
+
+    return {};
+}
+
+} // namespace XCEngine::UI::Editor