Ship workflow: detect + merge base branch, run tests, review diff, bump VERSION,
update CHANGELOG, commit, push, create PR. Use when asked to "ship", "deploy",
"push to main", "create a PR", "merge and push", or "get it deployed".
Proactively invoke this skill (do NOT push/PR directly) when the user says code
is ready, asks about deploying, wants to push code up, or asks to create a PR. (gstack)