refactor(yvan-lcc):优化 JsDemo 页面的代码执行逻辑

- 在代码模板中添加示例日志输出和日期对象- 优化 execute 函数的异步处理结构
- 调整代码格式，提高可读性

src/pages/JsDemo.vue

@@ -5,11 +5,14 @@ import YvSrcEditor from "../components/YvSrcEditor.vue"
 
 const code = ref(`
 
+log.info("测试打印日志，通过服务端控制台查看")
 const a = 111, b= 555;
 const sum = (a + b);
 print(a + "+" + b + " = " + sum);
 
 return {
+    sum,
+    date: new Date(),
     msg: "测试JS脚本",
 }
 `);
@@ -19,9 +22,9 @@ const res = ref("");
 function execute() {
     Request.request.post("/api/workbench/JsDemo@runJs", {
         jsCode: code.value,
-    }).then(data=> {
+    }).then(data => {
         res.value = JSON.stringify(data, null, 4);
-    }).catch(()=> {
+    }).catch(() => {
         res.value = "执行失败";
     });
 }