Add optional 'namespace' and 'kind-cluster-name' fields to spec
files. When 'namespace' is set, SO uses it instead of deriving one
from the cluster-id. When 'kind-cluster-name' is set, SO uses it
for the kube context instead of the cluster-id. Together these allow
multiple stacks with different cluster-ids (unique resource names)
to share a namespace and kind cluster.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>