/// Behavior shared by every kind of secret this CLI manages under one
/// `keyring.toml` (ADR-0022, secret storage per ADR-0135), implemented by
/// `commands::keyring::email::Identity`, `commands::keyring::bucket::
/// BucketConfig`, and the concrete `Entry` enum that wraps both
/// (`commands::keyring::store::Entry`) for storage (ADR-0023).
pub