marked <= 14 calls renderer.image(href, title, text); marked >= 15 passes
the token instead. With only the positional form handled, an upgrade of the
pinned CDN build would turn every session image into fallback text without
any error, so normalise both shapes and cover them with a unit test.
The tag name moves into session-image-contract.js so the Markdown renderer
no longer reaches it through the module that imports the .vue component,
which is what kept it out of Node's test runner.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
