Read-only production-promotion readiness check across every workspace project — for each repo with `origin/staging`, report how far staging is ahead of the production branch, whether staging's head passed its GitHub Actions runs, and any open staging→production PR, then print the exact commands for the owner to open, merge, and watch the promotion. Use when the user says "is staging ready for production", "prep the staging to production promotion", or runs /staging-to-production. Never opens or merges a PR, never pushes, never triggers a workflow, and never accesses production — the owner runs the printed commands. Promoting local to staging is /local-to-staging.
