Show HN: Open-source keyboard-only ASCII diagram builder TUI

I'm a visual person, and I easily express myself using diagrams. I thought, why not use diagrams in code comments? It has to be ASCII, and there are existing online solutions, but I want something simple in the terminal that allows me to use the keyboard. I couldn't find one, so I built this.

I know it could be sexier if written in Rust, but I used Python to keep it simple and approachable. It's less than 800 lines of code and fully type-annotated.

Let me know what you think!