The PR removed the documentId filter from list() along with the old
Geschichte.documents ManyToMany, but the document-detail page and its
frontend server still query GET /api/geschichten?documentId=<id> to show
related stories. Without the filter the endpoint silently returned every
published story. Restores the filter through a JPQL EXISTS check on
journey_items so only journeys that include the given document are returned.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>