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/buttons/Button.stories.js

@@ -1,4 +1,9 @@
 import Button from "../../app/components/buttons/Button";
+import {
+  BUTTON_PALETTE_OPTIONS,
+  BUTTON_TYPE_OPTIONS,
+  SIZE_OPTIONS,
+} from "../../lib/propNormalization";
 
 export default {
   title: "Components/Buttons/Button",
@@ -15,17 +20,17 @@ export default {
   argTypes: {
     buttonType: {
       control: { type: "select" },
-      options: ["filled", "outline", "ghost", "danger"],
+      options: [...BUTTON_TYPE_OPTIONS],
       description: "The button type (Figma prop)",
     },
     palette: {
       control: { type: "select" },
-      options: ["default", "inverse"],
+      options: [...BUTTON_PALETTE_OPTIONS],
       description: "The button palette (Figma prop)",
     },
     size: {
       control: { type: "select" },
-      options: ["xsmall", "small", "medium", "large", "xlarge"],
+      options: [...SIZE_OPTIONS],
       description: "The size of the button",
     },
     disabled: {