When a related project’s preview deployment is skipped or canceled by the Ignore Build Step, the dependent project can still receive that deployment’s URL in VERCEL_RELATED_PROJECTS, but requests to it return 404 because that deployment isn’t active.

Setting defaultHost on withRelatedProject() doesn’t help in this case: the related-project data is present and parseable, even though its URL is unusable.

Expected: When no usable preview deployment exists, the related-project data should either resolve to an active deployment or indicate that no preview URL is available, so callers can use a fallback.