Add new story for darkmode (#317)

* Add a new story for dark mode

* Reorganize storybook menu

* Fix command menu margins

* Fix tests

front/src/__stories__/App.mdx

@@ -0,0 +1,11 @@
+{ /* App.mdx */ }
+
+import { Canvas, Meta } from '@storybook/blocks';
+
+import * as App from './App.stories';
+
+<Meta of={App} />
+
+# App View
+
+<Canvas of={App.Default} />