[feature request] support setting environment variables in config

[networkhermit]

There are occasions when users want to inject environment variables to the terminal emulator, like the env config provided by alacritty.

Currently there are two ways in ghostty to achieve similar outcome:

1. Tweak the command configuration like command = /usr/bin/env WINIT_X11_SCALE_FACTOR="1.0" "${SHELL}" -l. Personally I think it is verbose and platform dependent.
2. Add environment variables in .zshrc/.bashrc/config.fish guarded by if [[ "$TERM_PROGRAM" = ghostty ]]; blocks. It works but I hope to use a more non-intrusive method.

Past closed disscussion in #3776.

[rhodes-b]

#4002
duplicate

I also dont think that #3776 is related, XDG_CONFIG_HOME should be set somewhere in your shell not the terminal

[networkhermit]

I don't think this is a strict duplicate of #4002, which is more about conditional ghostty configurations and have a much larger scope.

Yes. XDG_CONFIG_HOME is not a good example to set directly in terminal emulator. But the feature request - "Setting environment variables" is the same.

[mitchellh]

I think this feature request makes sense.

env = KEY=VALUE

The above makes the most sense, making it repeatable.

[mitchellh]

#5257