Expose the original Markdown source of each published Firekylin article at /<slug>.md.
For an article whose slug is hello-world:
GET /hello-world.md
Content-Type: text/markdown; charset=utf-8
The response body is the article's stored markdown_content without an added title or front matter. HEAD requests
return the same headers with an empty body.
Copy this package to Firekylin's plugin directory, or add @firekylin/plugin-markdown-route to the application's
dependencies, then restart Firekylin.
The route only exposes articles that are published, public, and whose publication time has arrived. Drafts, private
articles, scheduled articles, pages, and password-protected articles return 404 so the route cannot bypass normal
content protection.