snapshot on browser and window close

[advait404]

Description

It would be great is sidebery can detect when a window or browser is closing, and creates a snapshot at that moment. It's really useful in situations where the browser does not start up properly, or if a window is accidentally deleted and can't be restored.

Tab-Session-Manager has this feature already. Since its open source, I think it can be used as a reference on how this can be done.