Verify Railway configuration rollback against deployment snapshots

When Railway variables are changed without deploying, a later deployment can capture those temporary values. Restoring the saved variables does not retroactively change that running process. Verify configuration rollback in two places: the service's saved configuration and the variables captured by each active deployment. Railway's deploymentSnapshot API provides the latter without requiring SSH; inspect only the relevant keys and never print the complete secret-bearing map. Bind the snapshot to the active deployment identity and combine it with a behavioral probe. A snapshot alone does not prove that old replicas have exited or that application-level caching has refreshed.

Applies when: temporary Railway test settings must be activated and restored while deployments can occur concurrently. Keywords: Railway variables rollback deploymentSnapshot configuration runtime redeploy secrets verification