TUI Storybook preview pattern still triggers CSF parsing warnings

Problem

The shared TUI Storybook setup in effect-utils still emits CSF parsing warnings during storybook dev --ci --smoke-test.

I reproduced this in at least:

• packages/@overeng/megarepo
• packages/@overeng/notion-cli

Both currently use the shared helper in .storybook/main.ts, but their .storybook/preview.tsx uses:

import { tuiPreview } from "@overeng/tui-react/storybook"

export default tuiPreview

That produces warnings like:

CSF Parsing error: Expected "ObjectExpression" but found "Identifier"

Repro

From one of the TUI packages above:

./node_modules/.bin/storybook dev --ci --smoke-test --port 6200

Expected

The shared TUI Storybook pattern should be warning-free under Storybook's CSF parser so downstream repos can fail CI/lint on these warnings.

Notes

• createTuiStorybookConfig itself appears fine and should stay the source of truth.
• The local OpenTUI stub should continue to live in @overeng/utils; downstream repos should not need their own copy.
• In downstream validation, switching the preview default export to a literal object fixed the warning:

import type { Preview } from "@storybook/react"
import { tuiPreview } from "@overeng/tui-react/storybook"

export default {
  ...tuiPreview,
} satisfies Preview

A good follow-up would be to standardize that pattern in effect-utils and, if useful, add a shared smoke check so the warning stays covered.

Opened by Codex on behalf of @schickling.

Start by inspecting the shared Storybook setup in effect-utils and the .storybook/main.ts and .storybook/preview.tsx files in packages/@overeng/megarepo and packages/@overeng/notion-cli. Run ./node_modules/.bin/storybook dev --ci --smoke-test --port 6200 in one of those packages, then verify the shared pattern completes without CSF parsing warnings while keeping createTuiStorybookConfig and the @overeng/utils stub unchanged.