[Bug] Full runes mode support

[BlackySoul]

Describe the bug

If i set

compilerOptions: {
   runes: true,
}

in my svelte.config.js file, Storybook will fail to compile.

Steps to reproduce the behavior

1. Use default init project (npx sv create with storybook support)
2. Add

compilerOptions: {
   runes: true,
}

3. Run storybook
4. Error:

✘ [ERROR] node_modules/@storybook/addon-svelte-csf/dist/runtime/LegacyTemplate.svelte:14:2 Cannot use export let in runes mode — use $props() instead
https://svelte.dev/e/legacy_export_invalid [plugin vite-plugin-svelte:optimize]

Expected behavior

Storybook builds successfully

Screenshots and/or logs

Environment

• OS: iOS
• Node.js version: 24.11.0
• NPM version: 11.6.1
• Browser (if applicable): -
• Browser version (if applicable): -
• Device (if applicable): -

Additional context

Add any other context about the problem here.