next.js

2cc99c73 - docs: move insight error pages from vercel/front to canary (#94564)

docs: move insight error pages from vercel/front to canary (#94564) ### What? Moves 14 insight-kind error pages from `vercel/front/apps/next-site/content/errors-extra/` into this repo's `errors/` directory. ### Why? `nextjs.org`'s sync pipeline already clones `errors/` from canary on every deploy. `errors-extra/` is meant for in-flight drafts. These pages have stabilized, so they belong with the framework code they describe. This unblocks Docs Link Validation in #94496: cross-links from this repo's API docs (`cookies.mdx`, `headers.mdx`, `use-params.mdx`, `use-pathname.mdx`, `generate-metadata.mdx`, `generate-viewport.mdx`, etc.) to `/docs/messages/blocking-prerender-*` now resolve. ### How? Copied each `.mdx` verbatim. No content changes. Frontmatter (`kind: insight`) routes them through the FixOption renderer. Follow-up PR in `vercel/front` will remove the `errors-extra/` copies; until then the override wins on slug collision but the content is byte-identical. <!-- NEXT_JS_LLM_PR -->