Replace the aspirational alpha/beta/gamma model with the actual
deployment topology: prod runs blue/green in neuron-prod namespace,
stage is the single experiment slot in neuron-stage namespace.
The old script referenced neuron-alpha/beta/gamma deployments that
never existed. The new script uses blue-green-deploy.sh for prod
promotion and kubectl set image for stage experiments.
Loop: snapshot → deploy stage → evaluate → promote via blue/green.
Will Anderson