fix(scheduled-task): reject meta-only phrases in taskSpec parsing

Treat hollow requests like「我要做一个定时执行任务」as missing taskSpec so
WeChat preflight asks for both schedule and executable content instead of
accepting「执行」as a deliverable task description.

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

scheduled-task-intent.test.mjs

@@ -90,3 +90,24 @@ test('isScheduledTaskIntent excludes none', () => {
   assert.equal(isScheduledTaskIntent({ action: 'create_scheduled_task' }), true);
   assert.equal(isScheduledTaskIntent({ action: 'none' }), false);
 });
+
+test('meta scheduled-task phrases require task_spec clarification', () => {
+  for (const text of [
+    '我要做一个定时执行任务',
+    '定时自动执行任务',
+    '不是待办，定时执行任务',
+  ]) {
+    const intent = parseScheduledTaskIntent(text);
+    assert.equal(intent.action, 'create_scheduled_task', text);
+    assert.ok(intent.needsClarification?.includes('task_spec'), text);
+    assert.ok(intent.needsClarification?.includes('schedule'), text);
+    assert.equal(extractScheduledTaskSpec(text), null, text);
+  }
+});
+
+test('combined phrase keeps substantive taskSpec after time prefix', () => {
+  const text = '帮我创建一个定时执行任务，23：00执行，搜索今日新闻';
+  const intent = parseScheduledTaskIntent(text);
+  assert.equal(intent.needsClarification, undefined);
+  assert.match(intent.taskSpec, /搜索今日新闻/u);
+});