chore: catch up Storybook preview, coverage, and story hygiene

Stories were throwing without AuthModal/CreateFlow providers, autodocs was a no-op, and several DS/create-flow screens had no stories.

stories/pages/CommunityStructurePage.stories.js

@@ -0,0 +1,9 @@
+import { CommunityStructureSelectScreen } from "../../app/(app)/create/screens/select/CommunityStructureSelectScreen";
+
+export default {
+  title: "Pages/Create Flow/Community structure",
+  component: CommunityStructureSelectScreen,
+  parameters: { layout: "fullscreen" },
+};
+
+export const Default = {};