PATH is missing user folders

[tko]

Running on macos the PATH seen by the model appears to be /usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin which is missing all user folders and nothing works as all cli tools are unavailable.

Namely the environment mux runs in seems to be missing all folders set by

1. (fish) shell configuration
2. direnv using flake.nix

While the messaging suggests some attempts to use nix, those attempts fail because nix is not in PATH.

[ammario]

Hey, I think a part problem may be that the shell tool is bash, so we're loading your .bashrc and disregarding any fish config for bash tool calls. If you're launching Mux from the Applications launcher then there's no inheritance of desired environment variables. Otherwise if you're launching directly a terminal/fish you should get the right $PATH.

Thinking we could allow setting extra env in the global settings page. This is a common pattern (e.g. VS Code) but doesn't seem cleanest 🤔.

[tko]

FWIW I was able to work around this by setting PATH as secret 🙊🙈
Not great with flake updates though, just need to remember to refresh the secrets too.

[ammario]

@tko do you have thoughts on the approach here: #830?