docs: update Cron task dialog title and description

Update the dialog title from "编辑定时任务" / "新建定时任务" to the more concise "编辑任务" / "创建任务". Also change the description to better reflect the purpose, from explaining configuration details to the simpler "安排自动化的 AI 任务" (Schedule automated AI tasks). This makes the UI text clearer and more user-friendly.

src/pages/Cron/index.tsx

@@ -1520,10 +1520,10 @@ function CronTaskDialog({
               className="mb-2 text-[24px] font-normal tracking-tight text-[#171717] dark:text-[#f3f4f6]"
               style={{ fontFamily: "Georgia, Cambria, 'Times New Roman', Times, serif" }}
             >
-              {job ? '编辑定时任务' : '新建定时任务'}
+              {job ? '编辑任务' : '创建任务'}
             </h2>
             <p className="text-[14px] text-[#99A0AE] dark:text-gray-500">
-              现在可以为任务配置发送渠道和目标收件人，和 ClawX 的调度职责保持一致。
+              安排自动化的 AI 任务
             </p>
           </div>
           <button