RED — proves Erfolgskriterium 4 (INGEST-07): registering an adapter
whose portals include vergabe24 or aumass must throw DeniedPortalError,
including a mixed portals array with one denylisted entry. Also covers
legitimate register/get/activeAdapters happy paths. Fake adapter stub,
no real scraping.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
