Redeploy, restart, or rollback a Railway deployment via the API

Documented steps

1. Redeploy the same commit: mutation deploymentRedeploy(id) — returns { id, status }.
2. Restart a running deployment without rebuilding: mutation deploymentRestart(id).
3. Roll back to a previous deployment: mutation deploymentRollback(id) — returns { id, status }.
4. Cancel a building/queued deployment: mutation deploymentCancel(id).
5. Stop a running deployment: mutation deploymentStop(id).
6. Docs: https://docs.railway.com/integrations/api/manage-deployments