fix(scheduled-task): enable worker by default and add WeChat preflight

Scheduled automations were saved but never executed because the worker
required an explicit env flag. Follow H5_REMINDER_WORKER_ENABLED when unset,
add WeChat preflight to write tasks deterministically, and surface worker
warnings on create.

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/verify-scheduled-task-automation.mjs

@@ -4,7 +4,7 @@
  *
  * 默认：DB + mock worker 全链路（无需 Portal 进程）
  * 可选：
- *   VERIFY_SCHEDULED_TASK_LIVE=1  等待已开启 worker 的 Portal 到点执行（需 H5_SCHEDULED_TASK_WORKER_ENABLED=1）
+ *   VERIFY_SCHEDULED_TASK_LIVE=1  等待已开启 worker 的 Portal 到点执行（需 H5_SCHEDULED_TASK_WORKER_ENABLED=1 或未显式关闭且 H5_REMINDER_WORKER_ENABLED=1）
  *   --due-seconds=90              创建 N 秒后执行的一次性任务（live 模式用）
  */
 import assert from 'node:assert/strict';
@@ -204,7 +204,7 @@ async function testLivePortalWorker(pool, userId, { dueSeconds }) {
   pass('Live 任务已创建', `${waitSeconds}s 后执行，id=${created.id}`);
 
   console.log(`\n等待 Portal worker 执行（最多 ${waitSeconds + 120}s）…`);
-  console.log('请确认 Portal 进程已设置 H5_SCHEDULED_TASK_WORKER_ENABLED=1\n');
+  console.log('请确认 Portal 进程已开启 scheduled task worker（H5_SCHEDULED_TASK_WORKER_ENABLED=1，或未设置时 H5_REMINDER_WORKER_ENABLED=1）\n');
 
   const deadline = Date.now() + (waitSeconds + 120) * 1000;
   let terminal = null;