[michaelpratt-postman]

Summary

The docs call fern docs dev a local preview server, but they never say not to expose it or use it to host docs. This PR adds that guidance:

• Preview changes → Local development (canonical): fern docs dev is only for previewing on your own machine. Don't expose it through a reverse proxy, tunnel or open port, because it isn't built for public traffic and it shows role-gated content to anyone who can reach it (with no role selected, it shows all content). Readers are pointed to fern generate --docs for hosting and to preview links for sharing.
• CLI reference → fern docs dev: one sentence that links to fern generate --docs.

This is related to fern-api/fern#18540, which adds a tokenless, local-only POST /__fern/shutdown to fern docs dev. Behind a same-host reverse proxy that rewrites Host, anyone can reach that route. That PR isn't released yet, so this page doesn't mention shutdown; the guidance holds whether or not it ships.

Testing

• vale on both files: no new findings. The 4 existing errors are on unchanged lines.
• Every link already appears elsewhere in the docs (/learn/docs/authentication/features/rbac#preview-as-a-role, /learn/docs/preview-publish/publishing-your-docs), or is a same-page anchor (#preview-links, #fern-generate---docs).
• To confirm, open the PR's preview link and check /learn/docs/preview-publish/preview-changes#local-development and the fern docs dev accordion on /learn/cli-api-reference/cli-reference/docs-commands.

Link to Devin session: https://app.devin.ai/sessions/3e3169ab6d24438e9a11985d32d0707d
Open in Devin Desktop: https://app.devin.ai/desktop/session/3e3169ab6d24438e9a11985d32d0707d?variant=devin
Requested by: @michaelpratt-postman

[devin-ai-integration]

I'll fix CI failures and address comments from users with write access. I'll skip comments containing "(aside)".

• Disable automatic comment, CI, and merge conflict monitoring

[github-actions]

🌿 Preview your docs: https://fern-preview-devin-1793637849-docs-dev-not-for-hosting.docs.buildwithfern.com/learn

Here are the markdown pages you've updated:

• learn/cli-api-reference/cli-reference/docs-commands
• learn/docs/preview-publish/preview-changes