Om-Mittal486/PriorityBox ? reverse-engineered prompt

Build me a modern web app for tracking important emails in real time.

I want users to sign in with Google, connect Gmail, and then add the sender email addresses they care about. The app should show a dashboard with incoming emails from those senders, update automatically when new mail arrives, and let people open an email to read the full message in a modal. It should also support marking emails as read or unread, editing and deleting tracked senders, and a way to mark everything as read.

Make it feel polished and easy to use, with a clean responsive layout that works on mobile and desktop. Add dark mode and light mode with the choice saved between visits. When new mail comes in, play a sound and show a browser notification if possible. Use real time updates so the dashboard feels live.

Please make it a full stack app with a frontend and backend, and look up current docs online if you need to.