[fix] Fix high DPI FreeSnap preview issue

[feature] Support automatic screenshot after releasing the mouse unde…

…r the free snap function

[fix] Fix high DPI issue with free screenshots

[optimize]加速播放提示音

[optimize|doc]完善窗体控件截图；更新README文档

[feature|optimize]支持自定义文件名；添加菜单图标

[feature]支持徒手绘制区域截图

[optimize|chore]截取光标时背景色为透明；重构截图代码

[optimize|chore]截取光标时背景色为透明；重构截图代码

[feature|doc]支持录制GIF；支持更改应用外观；优化使用体验；更新README