Fix CLI sync workflow

[aaronpowell]

Summary

The CLI sync workflow is failing and not producing the expected synchronization outcomes.

Workflow links

• Workflow definition: https://github.com/github/awesome-copilot/blob/staged/.github/workflows/cli-for-beginners-sync.md
• GitHub run list: https://github.com/github/awesome-copilot/actions/workflows/cli-for-beginners-sync.lock.yml

Scope

• Reproduce failure and identify the precise break point
• Update workflow/job logic to restore sync behavior
• Validate outputs and downstream compatibility
• Capture any required version/config constraints in docs

Acceptance criteria

• Workflow passes on staged
• Sync output matches expected repository state changes
• No known blocking runtime or permission errors remain
• Documentation reflects current prerequisites and behavior

Parent

Part of #2076