Krikri::VarSubstitutor::UndecryptableVaultError

Raised when a template renders a vault blob none of the supplied secrets could open. Vault.maybe_decrypt_json leaves such a value encrypted rather than failing the parse, so the failure lands here, at the point of USE - matching real Ansible, which runs a playbook carrying a prod-only vault var quite happily on a dev box until something actually references it.