feat(wallpaper): replace nitrogen with feh

nitrogen was removed from Arch repos. Migrate to feh:
- Add feh to archsetup pacman installs
- Update .xinitrc, lf, ranger, and monitor script
- feh auto-creates ~/.fehbg for wallpaper restore

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/archsetup b/archsetup
index f733138..9329a0e 100755
--- a/archsetup
+++ b/archsetup
@@ -688,10 +688,9 @@ desktop_environment() {
     action="Desktop Environment Utilities" && display "subtitle" "$action"
 
     for software in brightnessctl network-manager-applet xclip rofi \
-                                  conky qalculate-gtk; do
+                                  conky qalculate-gtk feh; do
         pacman_install $software
     done;
-    # nitrogen removed from repos - TODO: migrate to feh
 
     aur_install caffeine-ng
     aur_install flameshot