Add workspace-level repo configure

[codeforester]

Summary

Add a workspace-level configure command that can apply the existing basectl repo configure repair path across repositories in the configured workspace or workspace manifest.

Desired behavior

• Add basectl workspace configure as the multi-repo wrapper.
• Default to the configured workspace root when no manifest is supplied.
• Support --manifest <path> for an explicit expected-repo set.
• Support --dry-run so users can preview the repo list and commands before applying changes.
• Delegate each repo to the existing basectl repo configure path instead of duplicating GitHub configuration logic.
• Continue per repo and report configured, skipped, and failed repositories.
• Document how this helps roll out shared Project schema changes such as the new Size=T option.

Notes

Default behavior should be conservative: only configure repositories that can be resolved to a local checkout and GitHub repository, and keep per-repo configuration idempotent.