Update README with usage notes

[AyushSinha2603]

Added usage notes for session launch and replay features.

[jestfortest]

A bit unnecessary, instead maybe improve something about the code instead.

[AyushSinha2603]

A bit unnecessary, instead maybe improve something about the code instead.

Thanks for the feedback. I understand that most of the points in the original section were already covered elsewhere in the README.

I've updated the PR to focus on a single first-run notice instead, as I was initially unsure whether the long loading time was expected behavior or an issue with my setup. I thought a brief note might help other first-time users with the same confusion.

I'll also take a look at the codebase and try to contribute a code improvement in a future PR once I'm more familiar with the project.

[jestfortest]

Ok that's good right now.