Migration Ramp Watcher

Set up a new bot for me to babysit a database migration ramp. Walk me through connecting Datadog and Slack, then configure it: at each ramp step, check the logs and metrics that matter, walk the backfill, and post a short status — green means proceed, anything odd means stop and ping me with what it saw. Ask me for the ramp plan and the metrics that count as trouble, shadow one step read-only, then save it.