new_editor: unify shared UI text measurement semantics

new_editor/include/XCEditor/Menu/UIEditorMenuBar.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <XCEditor/Foundation/UIEditorTextMeasurement.h>
+
 #include <XCEngine/UI/DrawData.h>
 
 #include <cstddef>
@@ -16,7 +18,8 @@ struct UIEditorMenuBarItem {
     std::string menuId = {};
     std::string label = {};
     bool enabled = true;
-    float desiredLabelWidth = 0.0f;
+    // Pure measured label width. Button padding is applied only in layout.
+    float measuredLabelWidth = 0.0f;
 };
 
 struct UIEditorMenuBarState {
@@ -81,6 +84,11 @@ struct UIEditorMenuBarHitTarget {
     std::size_t index = UIEditorMenuBarInvalidIndex;
 };
 
+float ResolveUIEditorMenuBarMeasuredLabelWidth(
+    const UIEditorMenuBarItem& item,
+    const UIEditorMenuBarMetrics& metrics = {},
+    const UIEditorTextMeasurer* textMeasurer = nullptr);
+
 float ResolveUIEditorMenuBarDesiredButtonWidth(
     const UIEditorMenuBarItem& item,
     const UIEditorMenuBarMetrics& metrics = {});