Markdown: display math through RaTeX, Mermaid through mermaid-rs-renderer, pictures from the owner's folder

Latex typesets with RaTeX to outlined SVG drawn by gpui's SvgRenderer at the
window's scale, loaded as an asset off the main thread. Diagram draws a
mermaid block in Mermaid's theme for the mode. MarkdownRenderer::base names
the folder pictures load from; data addresses decode, web ones stay unloaded.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

AGENTS.md

@@ -13,8 +13,9 @@ Ely GPUI Component. A component library for GPUI, in light and dark.
 - Web views: `wry` 0.57 (Apache-2.0 OR MIT, default features off, macOS only) lays a child WKWebView over the window.
 - Terminal: `alacritty_terminal` 0.26 (Apache-2.0, default features off, native only) for the grid, its parser and the pseudo-terminal; `futures` carries its events. `vte` 0.15 (Apache-2.0 OR MIT), the parser it re-exports, reads `AnsiText`'s codes alone, so colored output builds for wasm32.
 - Diffs: `similar` 3.2 (Apache-2.0) for line and word diffs and three-way merges; its `unicode` feature splits words at punctuation.
-- Markdown: `markdown` 1.0.0 (markdown-rs, MIT) reads GitHub's flavor and math into a syntax tree with byte positions for `MarkdownRenderer`, `MarkdownEditor`, the highlights, block ranges and outline. `BlockData::from_markdown` and its export still read with `pulldown-cmark` 0.13 (MIT, default features off); it adds GitHub's alerts, a callout's form, and reads each field's inline Markdown from the source by offset, as written.
+- Markdown: `markdown` 1.0.0 (markdown-rs, MIT) reads GitHub's flavor and math into a syntax tree with byte positions for `MarkdownRenderer`, `MarkdownEditor`, the highlights, block ranges and outline. `MarkdownRenderer` draws display math through `typography::Latex`, a ```` ```mermaid ```` block through `documents::Diagram`, and pictures from the owner's folder (`base`) or `data:` addresses (`base64` 0.22, MIT OR Apache-2.0); web pictures stay unloaded. Inline math shows as TeX: gpui text carries no inline pictures. `BlockData::from_markdown` and its export still read with `pulldown-cmark` 0.13 (MIT, default features off); it adds GitHub's alerts, a callout's form, and reads each field's inline Markdown from the source by offset, as written.
 - Pictures: `image` 0.25 (MIT OR Apache-2.0), the crate gpui decodes with, default features off; it turns decoded frames and rims map tiles.
+- Math and diagrams: RaTeX 0.1.14 (`ratex-parser`, `ratex-layout`, `ratex-svg` with `embed-fonts`, `ratex-types`; MIT, KaTeX's fonts OFL) typesets `Latex` to SVG with outlined glyphs; `mermaid-rs-renderer` 0.3.1 (MIT, default features off) draws `Diagram`. Both go through gpui's `SvgRenderer` at the window's scale, loaded as gpui assets off the main thread; `usvg` 0.46, gpui's own, reads a diagram's size. A RaTeX or Mermaid panic on parsed input becomes the element's error.
 - Maps: Natural Earth's 110m countries (public domain). `assets/maps/countries.geojson`, trimmed by `scripts/countries.py` to an ISO code, a name and positions to 0.01°, backs `maps::WorldMap`; the gallery's tiles are cut from the same file, z0 to z3, by `scripts/tiles.py` with Pillow.
 - Web: on wasm32, `web-time` 1.1 (MIT OR Apache-2.0) gives the `Instant` gpui's executor returns, std's own natively; jiff takes `js`, rust-embed `debug-embed`, similar `wasm32_web_time`. The gallery's web entry takes `gpui_web`, `wasm-bindgen`, `js-sys` and `web-sys` as wasm-only dev-dependencies, and a Hebrew cut of Noto Sans Hebrew 2.003 (OFL, `examples/gallery/fonts`): gpui_web asks the browser for emoji and CJK alone. The `wasm-bindgen` CLI at Cargo.lock's version and binaryen's `wasm-opt` finish the bundle.
 - Gallery: `examples/gallery`. Website: `frontend/` (Vite 8.3, pnpm 11, TypeScript, React 19.3, TanStack Router 1.170 in code-based routes, Lenis 1.3), in serro.ai's language: heavy titles over thin faint text, hairlines, one accent, full-screen sections, isometric line miniatures on a canvas. Pages name a story by its title's first part (`src/data.ts`'s `name`); scroll bars stay hidden; layouts step at 1024 and 768. Each story runs live from the gallery built for wasm32 through gpui_web, in a same-origin iframe, or, where a browser cannot run it, as a native capture. The Docs tab is Markdown in `frontend/src/docs/`, read in its `ORDER` and rendered by `marked` 18 (MIT) inside `vite.config.ts`'s `docs` plugin, so a bad guide fails `pnpm build` and the browser gets HTML alone; a fenced block tagged `example=NAME` shows `examples/docs/NAME.rs`, an example `scripts/check.sh` compiles as `docs_NAME`, so every full Rust sample on the site builds. The Showcase tab lists apps built with Ely from the public repo `ZacharyZhang-NY/Ely-GPUI-Showcases` on git.zacharyzhang.com (Gitea): manifests, PNG previews and Markdown READMEs, checked by its `scripts/catalog.mjs` (`marked`, `pngjs`, `twitter-text`), its stars refreshed by its CI. The mark is the letter E in iso blocks, its middle arm in the accent: one geometry in `src/iso/mark.ts`, drawn by the engine the miniatures use, worn by the header in the page's iso colors and by the favicon. Below 768px the header shows the mark without its word, which stays the home link's name; below 414px it drops the sound switch. Geist and Geist Mono (OFL, `@fontsource-variable`), Reicon icons (MIT, based on Solar Icons, CC BY 4.0, credited in the footer), simple-icons' Gitea mark (CC0). It deploys to Cloudflare Workers static assets through `npx wrangler` (4.143).