feat: scene traps, material legends, and scene editor window

Add trap overlays with session state, material legend editor/panel, and a dedicated scene editor window wired through IPC and project persistence.

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

app/renderer/sceneEditor/main.tsx

@@ -0,0 +1,20 @@
+import React from 'react';
+import { createRoot } from 'react-dom/client';
+
+import '../shared/ui/globals.css';
+import { EditorI18nProvider } from '../editor/i18n/EditorI18nContext';
+
+import { SceneEditorApp } from './SceneEditorApp';
+
+const rootEl = document.getElementById('root');
+if (!rootEl) {
+  throw new Error('Missing #root element');
+}
+
+createRoot(rootEl).render(
+  <React.StrictMode>
+    <EditorI18nProvider>
+      <SceneEditorApp />
+    </EditorI18nProvider>
+  </React.StrictMode>,
+);