v13.1.0

Environment-owned render validation

• Application.validate_render() now discovers mmdc through the execution environment and verifies both installed Mermaid and Mermaid CLI versions before rendering.
• Missing runtime packages return renderer_unavailable; an incompatible engine or CLI pair returns version_mismatch with supported and observed versions.
• Mermaiden remains a binary-free Python package: it does not bundle Node.js, Mermaid CLI, Puppeteer, Chrome, or a runtime image.
• CI and package verification now render through Puppeteer's version-compatible browser, including an isolated installed-wheel consumer proof.

Migration

1. Upgrade the Python package to mermaiden==13.1.0.
2. Read the supported pair from Application.mermaid_version and Application.mermaid_cli_version.
3. During environment or image construction, install those exact mermaid and @mermaid-js/mermaid-cli versions and run npx puppeteer browsers install.
4. Put that installation's node_modules/.bin on the runtime PATH.
5. Continue calling only Application.validate_render(); do not pass executable or browser paths into Mermaiden.

Application startup and render validation perform no downloads. Existing source rendering and snapshot behavior remain available without the external renderer environment.