feat(decman): manage npm packages and deploy sddm theme assets

system-config/source.py

@@ -6,9 +6,11 @@ concerns and its desktop-specific Hyprland and Noctalia configuration.
 
 import decman  # pyright: ignore[reportMissingImports]  # Provided by the Arch AUR package.
 
+from modules.npm_packages import Npm
 from modules.packages import configure_no_removal_guard
 from hosts import desktop
 
+decman.plugins[Npm.NAME] = Npm()
 configure_no_removal_guard()
 decman.modules += desktop()
-decman.execution_order = ["files", "pacman", "aur", "systemd"]
+decman.execution_order = ["files", "pacman", "aur", "npm", "systemd"]