Refresh wallpapers and update configs

- Set default stylix wallpaper to “The‑Southern‑Raiders.jpg” and comment
  out the old image.
- Bump helium AppImage to version 0.12.1.1 with updated URL and
  checksum.
- Switch NVIDIA driver package from beta to stable.
- Change “kys” alias to use systemctl poweroff and add “jezus” alias for
  reboot.

modules/home/bash/aliases.nix

@@ -50,7 +50,8 @@
 
     # System aliases
     # flush-codium = "sudo killall codium && sudo rm -rf ~/.config/VSCodium/Cache && sudo rm -rf ~/.config/VSCodium/CachedData";
-    kys = "shutdown now";
+    kys = "systemctl poweroff";
+    jezus = "systemctl reboot";
     ookla = "speedtest";
     hypr-cli = "hyprctl clients";