//! JSON layout engine — declarative layout system for JRPG screen composition.
//!
//! This module provides a declarative, JSON-driven layout engine that composes
//! screens from a tree of layout elements. Layout definitions are deserialized
//! from JSON and rendered by element-specific renderers.
//!
//! ## Architecture
//!
//! ```text
//! JSON Layout → Deserialize → ScreenLayout (element tree)
//! ↓
//! LayoutEngine::render()
//! ↓
//! Element renderers (border, text, tile, …)
//! ↓
//! Framebuffer
//! ```
//!
//! ## Sub-modules
//!
//! - [`types`] — Core type definitions (ScreenLayout, LayoutElement,
//! ElementParams, etc.)