iglass 1.3.0: always dark (or light)

Keep iglass dark (or light) while macOS or your Linux desktop switches between light and dark mode:

brew upgrade iglass      # or rerun the install script
iglass install --appearance dark

Works in iTerm2 and Ghostty. --appearance auto (the default) follows the system as before.

Added

• --appearance dark|light keeps iglass dark (or light) while macOS or your Linux desktop
  switches between light and dark mode. The default, auto, follows the system as before.
  Works in iTerm2 and Ghostty; status shows it, and Ghostty previews follow it.
  (#2)