#608 Claude/add hey cli plugin t3kr3y

Summary by cubic

Prepares this fork for the claude.ai marketplace by removing bin/.keep, which the marketplace sync rejects, and adds a daily workflow that merges upstream basecamp/hey-cli main back into the fork.

• The sync uses an octo-sts-minted short-lived token instead of GITHUB_TOKEN or a PAT, since upstream commits can touch .github/workflows.
• The workflow is gated to only run on justanotherspy/hey-cli.