- Add nixpkgs PR 483705 to bump codex from 0.89.0 to 0.92.0
- Disable overlay version overrides in favor of PR patches
- Replace deprecated pkgs.system with pkgs.stdenv.hostPlatform.system
- Replace deprecated xfce.thunar with thunar
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>