feat(任务调度): 增加任务开始和结束时间字段，优化任务调度逻辑

- 在任务类型、模型、接口和前端页面中新增 `start_date` 和 `end_date` 字段
- 优化任务调度逻辑，支持根据开始和结束时间设置任务的执行时间
- 前端新增间隔时间设置组件和 Cron 表达式选择器，提升用户体验
- 更新依赖包，引入 `element-plus` 和 `vue3-cron-plus-picker` 组件

backend/app/scripts/data/system_job.json

@@ -10,7 +10,9 @@
     "max_instances": 1,
     "jobstore": "default",
     "executor": "default",
-    "trigger_args": "*/10 * * * *",
+    "trigger_args": "0 0 12 * * ?",
+    "start_date": null,
+    "end_date": null,
     "status": false,
     "message": null,
     "description": null,
@@ -27,7 +29,9 @@
     "max_instances": 1,
     "jobstore": "default",
     "executor": "default",
-    "trigger_args": "*/20 * * * *",
+    "trigger_args": "0 0 12 * * ?",
+    "start_date": null,
+    "end_date": null,
     "status": false,
     "message": null,
     "description": null,
@@ -44,7 +48,9 @@
     "max_instances": 1,
     "jobstore": "default",
     "executor": "default",
-    "trigger_args": "*/30 * * * *",
+    "trigger_args": "0 0 12 * * ?",
+    "start_date": null,
+    "end_date": null,
     "status": false,
     "message": null,
     "description": null,