34 unit tests (fence extraction incl. nested/tilde/unclosed/render=false,
info-string parsing, slot substitution, diagnostic/figure escaping + SVG
script strip, byte-level dimension probing across 5 formats, content-box
math, image inlining incl. strict/remote/missing/data-URI paths). E2E gate
proves through the compiled binary: both fences render as vector text
(id-collision check), raw mermaid ships only via render=false, broken fence
yields the diagnostic block, and the relative fixture image rasterizes to
colored pixels (CRITICAL regression for the about:blank image fix).
--strict exits non-zero on a missing image.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>