//! Module: domain::metrics
//!
//! Responsibility: define pure metric-family selector values shared by runtime
//! metric projection, workflow queries, and endpoint DTOs.
//! Does not own: metric row DTO structs, metric recording, or CLI metrics
//! transport models.
//! Boundary: DTOs re-export these values to preserve the public API path while
//! internal code imports them from the domain owner.
use CandidType;
use Deserialize;
///
/// MetricsKind
///
/// Metric tier selector.
///