CLI: Add --config-dir flag to add command

[eric-blue]

Closes #

What I did

In the spirit of #26721, this PR adds a flag to the add so users can specify the config-dir of their Storybooks.

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

• stories
• unit tests
• integration tests
• end-to-end tests

Manual testing

This section is mandatory for all contributions. If you believe no manual test is necessary, please state so explicitly. Thanks!

Documentation

• Add or update documentation reflecting your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Checklist for Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli/src/sandbox-templates.ts

• Make sure this PR contains one of the labels below:

  Available labels

  • bug: Internal changes that fixes incorrect behavior.
  • maintenance: User-facing maintenance tasks.
  • dependencies: Upgrading (sometimes downgrading) dependencies.
  • build: Internal-facing build tooling & test updates. Will not show up in release changelog.
  • cleanup: Minor cleanup style change. Will not show up in release changelog.
  • documentation: Documentation only changes. Will not show up in release changelog.
  • feature request: Introducing a new feature.
  • BREAKING CHANGE: Changes that break compatibility in some way with current major version.
  • other: Changes that don't fit in the above categories.

🦋 Canary release

This PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

core team members can create a canary release here or locally with gh workflow run --repo storybookjs/storybook canary-release-pr.yml --field pr=<PR_NUMBER>

[nx-cloud]

☁️ Nx Cloud Report

CI is running/has finished running commands for commit 29078ce. As they complete they will appear below. Click to see the status, the terminal output, and the build insights.

📂 See all runs for this CI Pipeline Execution

---

✅ Successfully ran 1 target

• nx run-many -t build -c production --parallel=3

---

Sent with 💌 from NxCloud.

[eric-blue]

@yannbf

[jonniebigodes]

@eric-blue, if you're okay with it, can you include a minor adjustment to the documentation so we can include the option once this is approved/merged? Specifically here.

Let me know and we'll take it from there.

Have a fantastic day.

Stay safe

[eric-blue]

@jonniebigodes done!

[jonniebigodes]

@eric-blue appreciate you taking the time to make the documentation updates so promptly 🙏 ! From my end is all good, and I'll defer to @valentinpalkovic when to merge this.