This is a great piece of feedback, thank you so much!
We do utilize a login shell for executing commands, but we only support Bash and ZSH. So, it's a real Bash. However, there are some complications with environment interpolation and built-in commands; it's a known bug and we're working on it.
Unfortunately, I don't see how to allow using custom shells while providing a better command entering experience (i.e. zle or readline replacement). The core issue is that shells' interface is too primitive: it only consists of three streams with no per-job separation or anything; I wish Bash had a programmatic or REST-like interface.
We do utilize a login shell for executing commands, but we only support Bash and ZSH. So, it's a real Bash. However, there are some complications with environment interpolation and built-in commands; it's a known bug and we're working on it.
Unfortunately, I don't see how to allow using custom shells while providing a better command entering experience (i.e. zle or readline replacement). The core issue is that shells' interface is too primitive: it only consists of three streams with no per-job separation or anything; I wish Bash had a programmatic or REST-like interface.