//! # Reaction
//!
//! A lightweight, zero-cost input handling library designed for high-performance game engines.
//! Reaction decouples raw hardware events from your high-level game logic using an
//! action-based mapping system.
//!
//! ## Why Reaction?
//! - **Summative Resolution**: Opposing inputs (like A and D keys) correctly cancel each other out.
//! - **Additive Mouse Deltas**: No more lost movement data during high-speed frames.
//! - **State-Driven**: Query the state of any key, button, or axis at any time.