environment variables are not available to unmodified WASI Wasm modules

Thank you for making a-Shell, it already brings me a lot of joy. This is a feature request.

It's possible to execute a WebAssembly module in a-Shell, as documented at https://github.com/holzschu/a-shell#programming--add-more-commands, which is very useful. However, environment variables that are set in the shell are not propagated to the executed program. As far as I can see, the relevant code is:

https://github.com/holzschu/a-shell/blob/7572fb5b82e3b17c38402067784a86fd236711a7/hterm.html#L128

Environment variables are a critical input for many existing programs, so many more useful programs could be compiled to WebAssembly and used in a-Shell if this is implemented.