FIX: remove duplicate identifier_columns declaration in TableColumns DTO

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/modules/inputs/dtos/input.model.ts

@@ -14,8 +14,6 @@ export class TableColumns {
   @ApiPropertyOptional({ type: [Column] })
   references: Column[];
   @ApiProperty()
-  identifier_columns: string[];
-  @ApiProperty()
   destination: Record<'raw' | 'qualify', {
     table_name: string;
     table_schema: string;