Is your feature request related to a problem? Please describe.
I'm frustrated by the location of the config file on macOS. Almost all of my other command line utilities on macOS have their config file in the dot config folder. I have also explicitly set my XDG_CONFIG_HOME environment variable as well. It would be nice to have a way on macOS to force Aichat to put its config file in the dot config folder.

Describe the solution you'd like
I would like Aichat to place the config file in ~/.config by default, or at least respect my XDG_CONFIG_HOME environment variable.

Additional context
If this feature request is reasonable to the maintainer, I think I would be willing to put in a PR for this.