Add base-cli to the base-workspace manifest

[codeforester]

Summary

Add the standalone base-cli repository to workspace.yaml as a required Base workspace repository.

Context

The base_cli Python package has been migrated out of the Base repository into the dedicated base-cli repository, with a PyPI package available. The private workspace manifest should include the repository so workspace inventory and onboarding cover the complete Base development set.

Scope

• Add base-cli with its canonical GitHub URL.
• Mark it required and use the repository's main branch.
• Keep the change limited to the workspace manifest unless validation requires documentation updates.

Acceptance criteria

• workspace.yaml lists base-cli as a required repository.
• tests/validate.sh passes.
• The change is submitted as a pull request linked to this issue.