- Add gsettings-desktop-schemas for GNOME schema support on non-GNOME systems
- Add libstdc++.so.6 support via stdenv.cc.cc.lib for Python packages
- Include all required system libraries for Python virtual environment
- Set XDG_DATA_DIRS to include GNOME schemas path
- Reorganize Python environment configuration for better clarity
This resolves the issue where Light mode couldn't be selected in the
quickshell settings menu due to missing dependencies and library linking issues.
Celes Renata