fix(npcs): stop TipTap crash black screen in secondary windows

Guard TipTap getHTML under StrictMode, wrap secondary window roots in WindowErrorBoundary, and add stability regression tests.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/renderer/materials/main.tsx

@@ -3,6 +3,7 @@ import { createRoot } from 'react-dom/client';
 
 import '../shared/ui/globals.css';
 import { EditorI18nProvider } from '../editor/i18n/EditorI18nContext';
+import { WindowErrorBoundary } from '../shared/ui/WindowErrorBoundary';
 
 import { MaterialsApp } from './MaterialsApp';
 
@@ -13,8 +14,10 @@ if (!rootEl) {
 
 createRoot(rootEl).render(
   <React.StrictMode>
-    <EditorI18nProvider>
-      <MaterialsApp />
-    </EditorI18nProvider>
+    <WindowErrorBoundary title="Материалы">
+      <EditorI18nProvider>
+        <MaterialsApp />
+      </EditorI18nProvider>
+    </WindowErrorBoundary>
   </React.StrictMode>,
 );