refactor(jade): install wallpaper to system and separate xinitrc sections

- Install gruvbox wallpaper to /run/current-system/sw/share/backgrounds/jade/
- Split xinitrc into "Personal Configuration" and "jade Desktop Environment"
- Move wallpaper into jade/assets/ for flake extraction readiness

This makes jade fully repo-independent - the wallpaper is now part of jade's
system packages rather than referencing the nix-config repo. When extracted
as a flake, jade will be completely self-contained.

nixos/common/users/sajenim/jade/default.nix

@@ -22,6 +22,15 @@
       pkgs.unstable.gruvbox-material-gtk-theme
       # Install our XMonad and Xmobar configuration
       inputs.xmonad-config.packages.${pkgs.stdenv.hostPlatform.system}.default
+      # Install jade wallpapers
+      (pkgs.stdenv.mkDerivation {
+        name = "jade-wallpapers";
+        src = "${inputs.self}/nixos/common/users/sajenim/jade/assets";
+        installPhase = ''
+          mkdir -p $out/share/backgrounds/jade
+          cp -r $src/* $out/share/backgrounds/jade/
+        '';
+      })
     ];
 
     # Set default terminal for the desktop environment

nixos/common/users/sajenim/jade/xinitrc

@@ -1,22 +1,30 @@
 #!/bin/bash
 
-# Setup monitors (machine-specific - consider making configurable)
+#
+# Personal Configuration
+#
+
+# Setup monitors
 xrandr --output HDMI-A-0 --mode 1920x1080 \
   --output DisplayPort-0 --mode 2560x1440 --right-of HDMI-A-0
 
-# Apply wallpaper
-feh --bg-center ~/.repositories/personal/nix-config/assets/chinatown.png
-
-# Disable screen saver and DPMS features
-xset s off -dpms
-
 # Fix for pinentry bug on NixOS
 gpgconf --reload gpg-agent
 
-# Import X display into systemd user environment
+#
+# jade Desktop Environment
+#
+
+# Apply gruvbox-themed wallpaper
+feh --bg-center /run/current-system/sw/share/backgrounds/jade/chinatown.png
+
+# Disable screen saver and DPMS features
+xset s off -dpms
+
+# Import X display into systemd user environment for portal backends
 systemctl --user import-environment DISPLAY XAUTHORITY
 
-# Start XDG desktop portal backend
+# Start XDG desktop portal backend for GTK apps (file pickers, etc.)
 systemctl --user restart xdg-desktop-portal-gtk.service
 
 # Launch window manager