//! Abstract user-interface vocabulary for Smith.
//!
//! Frontends — terminal, graphical, web, mobile, RPC, eval — implement this
//! vocabulary; nothing here knows about any of them.
//!
//! Laws live in `SMH-SPEC-SPEC0001` (User interface abstraction):
//! plugins never query which frontend is active; they emit semantic UI
//! intents whose unsupported behavior is defined per intent.
//! Transcript appends are durable session events; presentation is
//! frontend detail.
//!
//! This crate is scaffold: types arrive with the first frontend that
//! consumes them under the plan that builds it.