docs: Update Geistdocs to 1.13.0 (#13412)
## Summary
- update the Turborepo docs app to `@vercel/geistdocs` 1.13.0
- use the package-owned Tailwind sources introduced since 1.11.1
- align docs content spacing and breadcrumb visibility with the new
container-responsive sidebar
https://turbo-site-git-docs-update-geistdocs-1130.vercel.sh/docs
## Testing
- `pnpm install --frozen-lockfile`
- `pnpm --filter docs check-types`
- `pnpm --filter docs lint`
- `pnpm --filter docs check-links`
- `OG_IMAGE_SECRET=<local value> pnpm --filter docs build`
- `pnpm format`
- `pnpm lint`
- production route smoke tests for HTML, `.md`, `Accept: text/markdown`,
agent requests, `llms.txt`, `sitemap.md`, `agents.md`, and `/api/search`
- desktop and mobile browser checks in light and dark themes, with no
runtime errors or horizontal overflow
- repository pre-push hooks
Upstream release: https://github.com/vercel/geistdocs/pull/160
Related upgrades:
- https://github.com/vercel/eve/pull/955
- https://github.com/vercel/chat/pull/727
