Fern docs monitoring

Draft. This outline will be expanded with verified, platform-specific detail.

How Fern sites typically break

• Navigation declared in docs.yml; pages removed from navigation become orphans. TODO(verify): config file name
• API reference pages generated from OpenAPI or Fern definitions move when operations are renamed.
• Heading ids generated from heading text.

What Fern catches, and what it misses

• Validation of the docs configuration on generate. TODO(verify): link checking
• Misses external links, anchors from other sites, sitemap drift and orphans.

Setting up redirects on Fern

• redirects entries in the docs configuration. TODO(verify): syntax

How PathIntact monitors a Fern site

• Detection via fern- class names and asset hosts TODO(verify); static reading with rendering fallback.