Tolan/backend/migrations/add_llm_tasks_lumi_first_line.sql

/*
  llm_tasks 表增加 Lumi 首句字段（A/B 组按任务配置不同首句）
  执行前请备份。MySQL 5.7+ / 8.0+
*/

SET NAMES utf8mb4;

ALTER TABLE `llm_tasks`
  ADD COLUMN `lumi_first_line` text COLLATE utf8mb4_unicode_ci NULL COMMENT 'Lumi 首句（A/B 组 greeting TTS）' AFTER `task_prompt`;

UPDATE `llm_tasks`
SET `lumi_first_line` = 'Hi, I''m Lumi, your university ambassador. I''m happy to talk with you today. How are you feeling?'
WHERE `lumi_first_line` IS NULL OR `lumi_first_line` = '';

ALTER TABLE `llm_tasks`
  MODIFY COLUMN `lumi_first_line` text COLLATE utf8mb4_unicode_ci NOT NULL COMMENT 'Lumi 首句（A/B 组 greeting TTS）';