Helm chart is now generic and self-hostable outside Tuist

The Helm chart is no longer tied to Tuist-specific infrastructure, so it can be used to self-host Hive anywhere. Default values are stripped of Tuist assumptions: host, image pull secrets, External Secrets Operator integration, and Postgres S3 backup are left unconfigured by default. A new secrets.existingSecret value lets operators bring their own Kubernetes Secret. Tuist’s production overlay moved to values-production.yaml, so helm template hive infra/helm/hive renders a generic set of resources without references to Tuist, 1Password, or hcloud.