Add starter room for learning rules

It would be great to have a training round where players can learn the rules. The space would only have minimal enemies (2?) and a few of the special spaces (chests, pits, etc). This would be walked through in the app so it explains what each move does and why.

The issue names no files, tests, or entry points. Begin by mapping where rounds, enemies, special spaces, and app walkthroughs are defined; clarify the tutorial flow and the intended minimal content before implementation. Done should include a playable starter round that explains each move and its purpose.

Written by the indexing model from the issue text.