feat(scheduler): run existing tasks immediately

docs/tools/scheduler.mdx

@@ -34,6 +34,14 @@ Create and manage scheduled tasks with natural language:
 - "Check server status every 2 hours"
 - "Remind me about the meeting tomorrow at 3 PM"
 - "Show all scheduled tasks"
+- "Run task a1b2c3d4 now"
+
+## Run an existing task now
+
+Use `action="run"` with a task ID to queue an immediate test run. Manual
+execution works for disabled tasks and does not enable, delete, or reschedule
+the task. Its original `next_run_at` remains unchanged. A task cannot be run
+manually while the same task is already executing on schedule.
 
 <Frame>
   <img src="https://cdn.link-ai.tech/doc/20260202195402.png" width="800" />

docs/zh/tools/scheduler.mdx

@@ -34,6 +34,11 @@ description: 创建和管理定时任务
 - "每隔 2 小时检查一下服务器状态"
 - "明天下午 3 点提醒我开会"
 - "查看所有定时任务"
+- "立即执行任务 a1b2c3d4"
+
+## 立即执行已有任务
+
+使用任务 ID 调用 `action="run"`，可以排队进行一次即时测试执行。禁用状态的任务也可手动执行，且不会因此被启用、删除或重新调度，原有 `next_run_at` 保持不变。同一任务正在按计划执行时，不允许重复手动执行。
 
 <Frame>
   <img src="https://cdn.link-ai.tech/doc/20260202195402.png" width="800" />