readme - screenshots with explanations

[neoneye]

Problem

There are 2 gifs at the moment. A few screenshots with explanation may be helpful.

Solution

I like the HexWalk readme. That will be something like this:

![ARC-Interactive editor overview](screenshots/arcinteractive_editor_overview1.png)

I like the SWE-Agent readme that has a top banner.

[neoneye]

It will be better to have the help screenshots inside the editor where it's needed, instead of in this readme.