chore: install terminfo files on codespaces
chore: install terminfo files on codespaces

Not sure why I didn't do this originally. It means I can let tmux use
`tmux-256color` as `$TERM` by default. It was working fine with
`xterm-256color`, although it's not recommended. May as well do it the
"right" way in any case.

wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent