//! Workflow engine
//!
//! Provides workflow definition management, instance creation, step execution, and state transitions.
//!
//! ## Module structure
//!
//! - [`model`] — Data structures + SQL queries
//! - [`engine`] — State machine core (WorkflowService)
//! - [`handler`] — Axum route handlers
//! - [`validate`] — Step definition validation + condition expression evaluation
pub mod engine;
pub mod handler;
pub mod model;
pub mod validate;
pub use engine::WorkflowService;
pub use model::{StepDef, StepLog, StepType, WorkflowDefinition, WorkflowInstance};