fix(graphql-codegen): generate barrel file for ORM-only mode

[pyramation]

Summary

Previously, the barrel file (index.ts) at the output root was only generated when both reactQuery and orm were enabled. This caused import errors when using ORM-only mode, as the output directory would have an orm/ subdirectory but no index.ts to re-export from it.

Now the barrel file is always generated (when not in dry-run mode), with exports based on which generators are enabled:

• ORM only: export * from './orm'
• React Query only: export * from './hooks'
• Both: export * from './types', export * from './hooks', export * from './orm'

This fixes the CI failure in constructive-db PR #444 where tests couldn't import createClient from the SDK.

Implementation

Added a new generateRootBarrel() function in barrel.ts using Babel AST for consistency with the rest of the codebase. The function conditionally adds export * from statements based on which generators are enabled.

Review & Testing Checklist for Human

• Verify the generated barrel file output format is correct (uses Babel AST, not string template)
• Verify the barrel file is generated correctly for ORM-only mode (the primary fix)
• Verify the barrel file is generated correctly for React Query-only mode
• Verify the barrel file still works correctly when both generators are enabled (regression check)
• After merging, regenerate the SDK in constructive-db to confirm the fix resolves the CI failure

Test Plan

1. Run codegen with orm: true only and verify output/index.ts contains export * from './orm'
2. Run codegen with reactQuery: true only and verify output/index.ts contains export * from './hooks'
3. Run codegen with both enabled and verify all three exports are present
4. Verify the generated file has the expected JSDoc header comment

Notes

• Requested by @pyramation
• Link to Devin run: https://app.devin.ai/sessions/6ba7bbfb91044b1fb6e7d26f49d5d2d2

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment and CI monitoring