```mermaid / ```excalidraw fences extract to placeholder tokens, render in
one diagram-render bundle tab per run (reset contract: bundle page reloads
after any render error), and substitute back as accessible <figure> blocks
with the raw source preserved in a comment. Render failures produce a loud
red diagnostic block, never silent raw code. render=false keeps a fence as
code; title="..." becomes the aria-label and caption.
Local images now actually render: page.setContent loads at about:blank
(tab-session.ts:194), so relative paths silently 404'd before. The pre-pass
resolves them against the markdown's directory, inlines as data URIs, probes
intrinsic dimensions from the bytes (pure-TS PNG/JPEG/GIF/WebP/SVG sniffing),
and downscales rasters wider than 2x the content box at 300dpi. Remote URLs
warn (offline posture, --allow-network exempts); missing files get a visible
placeholder; --strict hard-fails both for CI pipelines.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Garry Tan