fix: quiet empty transcription queue polls

internal/repository/implementations.go

@@ -191,14 +191,19 @@ func (r *jobRepository) ClaimNextTranscription(ctx context.Context, workerID str
 	var claimed models.TranscriptionJob
 	err := r.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
 		var candidate models.TranscriptionJob
-		if err := tx.
+		result := tx.
 			Where("status = ?", models.StatusPending).
 			Order("queued_at ASC, created_at ASC, id ASC").
-			First(&candidate).Error; err != nil {
-			return err
+			Limit(1).
+			Find(&candidate)
+		if result.Error != nil {
+			return result.Error
+		}
+		if result.RowsAffected == 0 {
+			return gorm.ErrRecordNotFound
 		}
 		now := time.Now()
-		result := tx.Model(&models.TranscriptionJob{}).
+		result = tx.Model(&models.TranscriptionJob{}).
 			Where("id = ? AND status = ?", candidate.ID, models.StatusPending).
 			Updates(map[string]any{
 				"status":           models.StatusProcessing,

internal/repository/job_queue_test.go

@@ -106,6 +106,16 @@ func TestJobRepositoryEnqueueAndClaimFIFO(t *testing.T) {
 	assert.Equal(t, newer.ID, claimed.ID)
 }
 
+func TestJobRepositoryClaimNextReturnsNotFoundWhenQueueEmpty(t *testing.T) {
+	db := openJobQueueTestDB(t)
+	repo := NewJobRepository(db)
+
+	claimed, err := repo.ClaimNextTranscription(context.Background(), "worker-a", time.Now().Add(time.Minute))
+
+	require.ErrorIs(t, err, gorm.ErrRecordNotFound)
+	require.Nil(t, claimed)
+}
+
 func TestJobRepositoryConcurrentClaimsDoNotDuplicateJobs(t *testing.T) {
 	db := openJobQueueTestDB(t)
 	user := createQueueTestUser(t, db)