refactor(storybook): consolidate dropdown stories into composed controls

src/sw/sw-header-dropdown.stories.tsx

@@ -0,0 +1,16 @@
+import type { Meta, StoryObj } from "@storybook/react-vite"
+import { ComposedDemo } from "./sw-header.stories"
+import "./sw-composed-controls.css"
+
+const meta = {
+  title: "SW/Header/Dropdown",
+  // Keep existing bookmarks while placing the single example under Dropdown.
+  id: "sw-header",
+  parameters: { layout: "fullscreen", controls: { disable: true } },
+} satisfies Meta
+export default meta
+
+export const ComposedControls: StoryObj<typeof meta> = {
+  name: "Composed Controls",
+  render: () => <ComposedDemo />,
+}