[feature] Browser notification & notification count on the extension icon

[EdiTurn]

Version and OS 0.45.25 on docker

Is your feature request related to a problem? Please describe. Nope

Describe the use-case and give concrete real-world examples Currently, this project has a browser extension, but only used for adding new watches. So I think these features are useful with this extension:

1. Add the ability to send browser notifications of the changes, and click the notification to open the website/diff page.
2. Show an unread count badge on the notification icon.

[dgtlmoon]

Add the ability to send browser notifications of the changes, and click the notification to open the website/diff page.

This can be solved with https://developer.mozilla.org/en-US/docs/Web/API/Notification https://useinsider.com/what-is-web-push-notification/

Show an unread count badge on the notification icon.

Maybe also solved with some hacking of the favicon :)