优化结构

internal/data/system/media_upload.go

@@ -90,11 +90,17 @@ func (r *mediaRepo) FailUploadSession(ctx context.Context, id uint) error {
 	return r.data.DB().WithContext(ctx).Model(&uploadSessionPO{}).Where("id = ?", id).Update("status", "failed").Error
 }
 func (r *mediaRepo) CompleteUploadSession(ctx context.Context, id uint, key string, mediaID uint) error {
-	return r.data.DB().WithContext(ctx).Model(&uploadSessionPO{}).Where("id = ?", id).Updates(map[string]any{"status": "completed", "storage_key": key, "media_id": mediaID}).Error
+	result := r.data.DB().WithContext(ctx).Model(&uploadSessionPO{}).Where("id = ? AND status = ?", id, "merging").Updates(map[string]any{"status": "completed", "storage_key": key, "media_id": mediaID})
+	if result.Error != nil {
+		return result.Error
+	}
+	if result.RowsAffected != 1 {
+		return system.ErrUploadSessionNotFound
+	}
+	return nil
 }
 func (r *mediaRepo) DeleteUploadSession(ctx context.Context, id uint) error {
-	// The compatible flow uses GORM's normal Delete here, retaining the soft-deleted session
-	// for audit/recovery rather than physically removing it.
+	// Upload sessions are staging records; cleanup physically removes them and their chunks.
 	return r.data.DB().WithContext(ctx).Unscoped().Delete(&uploadSessionPO{}, id).Error
 }
 func (r *mediaRepo) UpsertChunk(ctx context.Context, uploadID uint, v *system.UploadChunk) error {