Returns a single supply chain attack campaign by ID. Same shape as one item
from the campaigns list; package PURLs are not inlined — fetch them from the
paginated /threat-campaigns/:campaign_id/packages resource instead.

Useful for filling in cached campaign metadata client-side when crawling the
campaigns list or packages feed.

Authentication: Organization API token, OAuth2, or NextAuth session.
Required token scope: threat-campaigns:list.

This endpoint requires an Enterprise Plan with the Threat Feed add-on.