Fix Light mode selection in quickshell settings

- 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.

packages/dots-hyprland-packages.nix

@@ -26,6 +26,7 @@ let
   widgetPackages = with pkgs; [
     fuzzel
     glib # for gsettings
+    gsettings-desktop-schemas # GNOME schemas for non-GNOME environments
     hypridle
     hyprutils
     hyprlock
@@ -71,6 +72,18 @@ let
     gobject-introspection
     sassc
     opencv4 # python-opencv
+    
+    # Additional system libraries needed for Python packages
+    stdenv.cc.cc.lib # provides libstdc++.so.6
+    glibc
+    zlib
+    libffi
+    openssl
+    bzip2
+    xz
+    ncurses
+    readline
+    sqlite
   ];
 
   # Additional packages that might be needed