chore: import upstream snapshot with attribution

crates/jcode-render-core/src/lib.rs

@@ -0,0 +1,42 @@
+//! # jcode-render-core
+//!
+//! Backend-neutral document/render model shared by jcode's front-ends (the
+//! ratatui TUI and the desktop GPU UI).
+//!
+//! The pipeline is split at the seam where backends actually differ:
+//!
+//! ```text
+//!   text ─▶ parse_markdown ─▶ Document (neutral blocks/spans) ─▶ wrap ─▶ adapter ─▶ backend draw
+//! ```
+//!
+//! Everything up to and including wrapping is shared here. Each front-end owns
+//! only a thin adapter: it resolves [`model::StyleRole`] to concrete colors and
+//! turns [`model::StyledLine`]s into its own draw primitives (`ratatui::Line`
+//! for the TUI, glyph runs for the desktop), and supplies a
+//! [`wrap::WidthMeasure`] for its width units.
+//!
+//! This model is extracted from the *working* TUI markdown renderer
+//! (`jcode-tui-markdown`); that renderer remains authoritative until this core
+//! reaches parity, after which front-ends migrate onto it.
+
+pub mod markdown;
+pub mod math;
+pub mod model;
+pub mod preprocess;
+pub mod reasoning;
+pub mod wrap;
+
+pub use markdown::parse_markdown;
+pub use math::{render_display_latex, render_inline_latex};
+pub use model::{
+    Alignment, Block, BlockKind, Document, FillRole, StyleRole, StyledLine, StyledSpan, TextAttrs,
+};
+pub use preprocess::{escape_currency_dollars, normalize_latex_math};
+pub use reasoning::{
+    REASONING_SENTINEL, reasoning_line_markup, reasoning_partial_markup,
+    reasoning_summary_line_markup,
+};
+pub use wrap::{ColumnWidth, WidthMeasure, wrap_line, wrap_lines};
+
+#[cfg(test)]
+mod tests;