Introduces TranscriptionQueueProjection and TranscriptionWeeklyStatsProjection interfaces so column reordering in native SQL can never silently produce wrong data. Removes the four type-coercion helpers (toUUID, toLocalDate, toInt, toLong) from TranscriptionQueueService. Covered by TranscriptionQueueServiceTest (6 tests). Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>