feat: Add FaceAI integration with handoff and return functionality

- Introduced a new workspace for FaceAI in package.json.
- Implemented FaceAI handoff logic in faceai_handoff.php, including identity verification and token signing.
- Created faceai_return.php to handle return requests from FaceAI, validating tokens and forwarding results.
- Developed faceai_simulator.php and faceai_simulator_view.php for simulating the FaceAI interface with demo photos.
- Enhanced rus-ecom-240621.js to support new FaceAI features, including dynamic URL building and button integration.
- Added faceai_config.php for configuration management, including environment variable handling and utility functions.
- Updated HTML structure and styles in simulator view for better user experience.

faceai/apps/frontend/src/legacyAssets.js

@@ -0,0 +1,26 @@
+const legacyAssetBaseUrl = (import.meta.env.VITE_LEGACY_ASSET_BASE_URL || '/legacy-static').replace(/\/$/, '');
+
+export function legacyAsset(path) {
+  return `${legacyAssetBaseUrl}${path.startsWith('/') ? path : `/${path}`}`;
+}
+
+export function injectLegacyStylesheets() {
+  const stylesheets = [
+    legacyAsset('/vendor/bootstrap/css/bootstrap.min.css'),
+    legacyAsset('/css/font-awesome.min.css'),
+    'https://fonts.googleapis.com/css?family=Roboto:300,300i,400,400i,700,700i',
+    legacyAsset('/css/custom-style.css')
+  ];
+
+  stylesheets.forEach((href) => {
+    if (document.head.querySelector(`link[data-legacy-href="${href}"]`)) {
+      return;
+    }
+
+    const link = document.createElement('link');
+    link.rel = 'stylesheet';
+    link.href = href;
+    link.dataset.legacyHref = href;
+    document.head.appendChild(link);
+  });
+}