perf: memoize derived render data

src/App.tsx

@@ -127,6 +127,27 @@ const VIEW_KEYS = new Set<WebViewKey>([
 ]);
 
 const PUBLIC_VIEW_SET = new Set<WebViewKey>(["home", "login", "community", "more", "dialogGenerator", "userAgreement", "privacyPolicy", "not-found"]);
+const LEGACY_PAGE_STYLE_VIEWS = new Set<WebViewKey>([
+  "login",
+  "workbench",
+  "canvas",
+  "community",
+  "communityReview",
+  "communityCaseAdd",
+  "assets",
+  "ecommerce",
+  "ecommerceHub",
+  "digitalHuman",
+  "characterMix",
+  "more",
+]);
+
+let legacyPageStylesPromise: Promise<unknown> | null = null;
+
+function loadLegacyPageStyles(): Promise<unknown> {
+  legacyPageStylesPromise ??= import("./styles/pages/legacy-pages.css");
+  return legacyPageStylesPromise;
+}
 
 function normalizeViewKey(rawView: string): WebViewKey {
   const normalized =
@@ -357,6 +378,12 @@ function App() {
     if (isEcommerceActive && !ecommerceEverMounted) setEcommerceEverMounted(true);
   }, [isEcommerceActive]); // eslint-disable-line react-hooks/exhaustive-deps
 
+  useEffect(() => {
+    if (LEGACY_PAGE_STYLE_VIEWS.has(activeView) || ecommerceEverMounted) {
+      void loadLegacyPageStyles();
+    }
+  }, [activeView, ecommerceEverMounted]);
+
   // Dismiss boot splash after first render
   useEffect(() => {
     const splash = document.getElementById("app-boot-splash");