As far as I can see, it seems to me that every command issued by the `ExecFuture` system, does not have the `$HOME` environment variable.
Documentation:
https://we.phorge.it/book/arcanist/class/ExecFuture/
Among other things, this is a problem in the Config page (`/config`) since it issues `git log` but without an `$HOME` it cannot parse any `.gitconfig` and cannot read `safe.directory` and so it fails.
Questions:
1. Is `$HOME` missing by design in ExecFuture? I think no.
2. Should we enable `$HOME` as default? I think yes.