Switch openbao-activity-core ClusterSecretStore to interim coulombcore
token auth like forgejo/reuse, broaden the activity-core ESO policy to
include the shared issue-core runtime path, and document ESO-managed rotation.
Introduce external-secrets-forgejo policy/role, ClusterSecretStore
openbao-forgejo (forgejo namespace), and make openbao-configure-external-secrets-forgejo.
Define platform-owned AppProjects, root app-of-apps, repository registration
templates, and tenant onboarding docs so issue-core can deploy via ArgoCD.
Ignore encrypted repository secrets locally and cross-link OpenBao delivery
guidance with the new GitOps contract.