Summary

Adds support for CSF Next, the new Storybook configuration and story authoring format available experimentally in Storybook 10.

CSF Next replaces the traditional export default meta / export const Story pattern with a definePreview() / defineMain() / meta.story() API that provides full type safety, composability, and better IDE support.

Core changes

• definePreview() support — Re-exports definePreview from @storybook/react and adds resolveAnnotations() in Start.tsx to unwrap the opaque Preview object that definePreview() produces. We extract .input (the user's plain config) rather than using .composed, which includes web-specific core annotations that depend on a browser environment not available on-device.
• defineMain() support — Adds a typed defineMain() helper exported from @storybook/react-native/node for type-safe main config.
• StorybookConfig type refinement — Moved to types/config.ts, now uses Preset type for addons instead of loose string/object union.
• Improved type annotations — Replaces any[] with ModuleExports[] and unknown throughout Start.tsx.

Examples and tests

• Adds .factories.stories.tsx variants for all existing example stories demonstrating the factories API
• Adds .factories.test.tsx portable story tests for factories stories
• Adds .rnstorybook-nofactories/ config directory to test both config styles side-by-side
• Updates metro.config.js and App.tsx to support switching between factories and non-factories configs

How the factories API looks

preview.tsx (before):

import type { Preview } from '@storybook/react-native';

const preview: Preview = {
  parameters: { /* ... */ },
};
export default preview;

preview.tsx (after):

import { definePreview } from '@storybook/react-native';

export default definePreview({
  addons: [],
  parameters: { /* ... */ },
});

Stories (before):

const meta = { component: Button } satisfies Meta<typeof Button>;
export default meta;
export const Primary: StoryObj<typeof meta> = { args: { label: 'Click' } };

Stories (after):

const meta = config.meta({ component: Button });
export const Primary = meta.story({ args: { label: 'Click' } });

Test plan

• pnpm build completes successfully
• pnpm test passes — both factories and non-factories story tests
• Run expo example with factories config — stories render correctly
• Run expo example with non-factories config — stories render correctly
• definePreview() config is properly unwrapped (parameters, decorators, etc. are applied)
• defineMain() provides type checking for main config