Move the hasTranscription existence query out of the shared getDocumentById
into a dedicated getDocumentDetail used solely by GET /api/documents/{id}.
The flag is only consumed by the detail page, so the extra EXISTS query no
longer runs for the many internal getDocumentById callers (e.g. the
Geschichte resolve loop and the dashboard resume path). Behaviour of the
detail endpoint is unchanged.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>