feat: Add Storybook for component documentation, testing, and development (#34907)

Co-authored-by: Echo <ChaosExAnima@users.noreply.github.com>
Co-authored-by: Renaud Chaput <renchap@gmail.com>

.storybook/preview.ts

@@ -0,0 +1,29 @@
+import type { Preview } from '@storybook/react-vite';
+
+// If you want to run the dark theme during development,
+// you can change the below to `/application.scss`
+import '../app/javascript/styles/mastodon-light.scss';
+
+const preview: Preview = {
+  // Auto-generate docs: https://storybook.js.org/docs/writing-docs/autodocs
+  tags: ['autodocs'],
+  parameters: {
+    layout: 'centered',
+
+    controls: {
+      matchers: {
+        color: /(background|color)$/i,
+        date: /Date$/i,
+      },
+    },
+
+    a11y: {
+      // 'todo' - show a11y violations in the test UI only
+      // 'error' - fail CI on a11y violations
+      // 'off' - skip a11y checks entirely
+      test: 'todo',
+    },
+  },
+};
+
+export default preview;