Browser Notification on Deploy Success/Failiure

### What problem are you trying to solve?

For more DX convenience it would be nice, if Deno Deploy could send browser notification abut the build/deploy status.

### Describe the solution you'd like

On Deploy success or faliure -> send a browser notification.

### Describe alternatives you've considered

Opening the project on deploy.deno.com and hitting refresh a couple of times. (A bit sad that the page needs refreshes like Github when it comes to observing builds.)

### Documentation, Adoption, Migration Strategy

_No response_

The issue requests browser notifications for Deno Deploy build and deployment success or failure, but names no files, tests, or entry points. Start by locating the deployment status flow and notification support; done means users receive a notification for both successful and failed deployments without repeatedly refreshing the project page.

Written by the indexing model from the issue text.