feat(proj): init

mobile/widgetbook/lib/addons/device_frame_addon.dart

@@ -0,0 +1,11 @@
+import 'package:widgetbook/widgetbook.dart';
+
+/// Common phone frames for visual QA (ViewportAddon replaces DeviceFrameAddon).
+ViewportAddon buildDeviceFrameAddon() {
+  return ViewportAddon([
+    Viewports.none,
+    IosViewports.iPhone13,
+    IosViewports.iPhone13Mini,
+    AndroidViewports.samsungGalaxyS20,
+  ]);
+}