Add findByGeschichteIdWithDocument() to JourneyItemRepository with a
LEFT JOIN FETCH on document. getItems() now uses this query so that all
documents for a journey's items are loaded in a single SQL round-trip.
toView() now reads item.getDocument() directly from the already-fetched
association instead of issuing a separate documentService.getSummaryById()
call per item.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>