//! Agent handoff extension — dynamic same-thread agent switching.
//!
//! Manages agent variant switching within a running agent loop:
//!
//! 1. `HandoffState` tracks active and requested agent variants.
//! 2. `HandoffPlugin` reads state and applies agent overlays dynamically.
//! 3. `AgentOverlay` defines per-variant overrides (system prompt, model ID, tools).
//!
//! No run termination or re-resolution occurs — handoff is instant.
pub use ;
pub use ;
pub use ;
pub use AgentOverlay;