Declares the Cloud Run service, runtime account, secrets, and orca_push
database behind push_gateway_enabled, true only in production. The deploy
workflow is gated like the relay's, deploys with no traffic, probes /ready
and a validate-only FCM send, then shifts traffic. It runs as the shared
production deploy account because the Cloud SQL rollout lease grant is
foundation-owned; its extra authority is three bindings on the push service.
docs/push-gateway.md carries the import commands for the resources created
by hand and the APNs key rotation procedure.
Phase 6 of the relay split: the relay's deploy/operate surface moves under cloud/ with 24 cloud-* workflows gated on ORCA_CLOUD_OPERATIONS_ENABLED, the Cloud SQL rollout lease action, the relay Terraform root (dual-accept identities for both repositories), scripts, docs, CODEOWNERS, and a terraform validate job in Cloud Verify.