CPU Profiler auto stop timer [Improvement]

Suggestion to add a customizable automatic stop for a specified number of seconds.

I spent several days optimizing the speed of the library on Dart. To compare two states before and after, you need to measure at the same time interval. I had to additionally use a timer app to record roughly 10 second sections. During optimization, this operation has to be done hundreds of times. It would be more convenient to have an input field next to the Stop button indicating the number of seconds before automatic stop.

首先定位 CPU Profiler 屏幕及其现有的 Stop 控件，然后跟踪当前如何处理 profiling 时长。完成标准是在 Stop 旁提供秒数输入，并在所选时间间隔后自动结束 profile，同时该行为可用于重复比较。

由索引模型根据 Issue 内容生成。