fix(record): propagate env of vhs process to record terminal

[tr3mor]

Hello,
This pr broke env variables propagation to terminal spawned by record command.
From Env description

	// If Env is nil, the new process uses the current process's
	// environment.

Appending VHS_RECORD makes it not nil, so it resets env. This pr fixes #554.

For example with the latest released vhs

root# echo $HOME
/var/root
root# vhs record
sh-3.2# echo $HOME
sh-3.2# env
VHS_RECORD=true
PWD=/private/var/root
SHLVL=1
_=/usr/bin/env

The simplest solution is to get env of the main process and then append VHS_RECORD
The same example with the build from this PR

root# echo $HOME
/var/root
root# ./vhs record
sh-3.2# echo $HOME
/var/root

sh-3.2# env
TERM=xterm-ghostty
SHELL=/bin/sh
LC_ALL=en_US.UTF-8
USER=root
SUDO_UID=503
SSH_AUTH_SOCK=/private/tmp/com.apple.launchd.4WqxVicPZH/Listeners
__CF_USER_TEXT_ENCODING=0x0:0:0
PATH=/usr/local/bin:/System/Cryptexes/App/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin:/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin:/Users/REDACTED/go/bin:/Users/REDACTED/.local/share/zinit/polaris/bin:/opt/homebrew/bin:/opt/homebrew/sbin:/Applications/Ghostty.app/Contents/MacOS:/Users/REDACTED/Library/Application Support/JetBrains/Toolbox/scripts
MAIL=/var/mail/root
VHS_RECORD=true
PWD=/Users/REDACTED/personal/vhs
LANG=en_US.UTF-8
HOME=/var/root
SUDO_COMMAND=/bin/sh
SHLVL=2
LOGNAME=root
SUDO_GID=20
COLORTERM=truecol

Let me know if you see a better solution.

[tr3mor]

It looks like lint issues are unrelated to my change, so I don't think I need to fix them.

[bashbunni]

@tr3mor agreed, will take a look at this. Thanks so much for spotting this issue and coming up with a solution