RAILIANCE-WP-0011-T01: propose OpenBao path
platform/workloads/reuse/reuse-surface/runtime-secrets with
REUSE_SURFACE_TOKEN and REUSE_SURFACE_FORGEJO_WEBHOOK_SECRET, matching
read policy, and metadata review for Railiance01 interim ESO delivery.
Add workload KV lane for Nextcloud WebDAV token, URL, and age recovery
escrow at platform/workloads/railiance/backup/offsite-lane. Apply read
policy and OIDC role railiance-backup-workload-kv-read; wire forgejo-backup
to load credentials from OpenBao when env is unset.
Introduce external-secrets-forgejo policy/role, ClusterSecretStore
openbao-forgejo (forgejo namespace), and make openbao-configure-external-secrets-forgejo.