把只赋值一次的 overview 改成 const 三元

src/view/ui-editor/index.tsx 用三元表达式声明 overview，去掉 let + if/else 两处赋值，表达不可变意图

apps/ai-game-creator-shell/src/view/ui-editor/index.tsx

@@ -79,9 +79,8 @@ export default function UiEditorPage({
   const [showFrame, setShowFrame] = useState(true);
   const [showOriginImage, setShowOriginImage] = useState(true);
   const [showComponent, setShowComponent] = useState(false);
-  let overview: ReactNode;
-  if (session.input.activeStep === 'structure-recognition') {
-    overview = (
+  const overview: ReactNode =
+    session.input.activeStep === 'structure-recognition' ? (
       <RecognitionOverview
         uiTrees={session.input.uiTrees}
         onFocusStatusNode={(treeId, nodeId) => {
@@ -89,9 +88,7 @@ export default function UiEditorPage({
           session.input.highlightStatusField(nodeId, 'layout_status');
         }}
       />
-    );
-  } else {
-    overview = (
+    ) : (
       <SeparationOverview
         uiTrees={session.input.uiTrees}
         sprites={session.input.sprites}
@@ -102,7 +99,6 @@ export default function UiEditorPage({
         }}
       />
     );
-  }
   const saveDisabled =
     session.save.isSaving ||
     session.save.isGenerating ||