Add Ventoy support and refactor wallpaper handling

Introduce a `ventoy.enable` option (default false) and import the new
`modules/core/ventoy.nix` in the core module list. All host
`system-modules.nix` files now disable Ventoy explicitly.

Make the boot wallpaper configurable by importing `stylixImage` from the
host’s `variables.nix` and using it in `modules/core/boot.nix`.

Update each host’s `variables.nix` to set a default wallpaper and keep
many alternatives commented out.

Remove the obsolete `restart.noctalia` and `screenshootin` scripts,
their Nix wrappers, and the related Hyprland keybinding.

Add a collection of new wallpaper files and delete the old, unused
images.

hosts/default/system-modules.nix

@@ -36,6 +36,11 @@ _: {
   */
   affinity.enable = false; # Affinity: professional graphics suite
 
+  /*
+  Utilities / Misc
+  */
+  ventoy.enable = false; # Ventoy: New Bootable USB Solution with GUI support
+
   packages = {
     /*
     Container & Packaging

hosts/default/variables.nix

@@ -48,20 +48,21 @@
   # This will set your color palette
   # Default background
   # Add new images to ~/garandos/wallpapers
-  stylixImage = "attack-on-titan-mikasa-ackerman.jpg";
-  #stylixImage = "DW_Pacts.jpg";
-  #stylixImage = "edward-elric-fullmetal-alchemist.jpg";
-  #stylixImage = "fire-nation.jpg";
-  #stylixImage = "four-elements.jpg";
-  #stylixImage = "fullmetal-alchemist-5120x2880-10399.png";
-  #stylixImage = "Grounded_Wallpaper_4K.jpg";
-  #stylixImage = "jablon.jpg";
-  #stylixImage = "rammstein-log-two.jpg";
-  #stylixImage = "rammstein-logo-one.jpg";
-  #stylixImage = "rammstein-logo-three.jpg";
-  #stylixImage = "rammstein-one.jpg";
-  #stylixImage = "1346530.jpeg";
-  #stylixImage = "The-Southern-Raiders.jpg";
+  stylixImage = "Attack-on-Titan-1.jpg";
+  # stylixImage = "Attack-on-Titan-2.jpg";
+  # stylixImage = "Attack-on-Titan-3.jpg";
+  # stylixImage = "Avatar-1.jpg";
+  # stylixImage = "Avatar-2.jpg";
+  # stylixImage = "Avatar-3.png";
+  # stylixImage = "Avatar-4.jpg";
+  # stylixImage = "Edge-of-Tomorrow-1.jpg";
+  # stylixImage = "Friren-1.jpg";
+  # stylixImage = "Friren-2.jpg";
+  # stylixImage = "Friren-3.jpg";
+  # stylixImage = "Jablon.png";
+  # stylixImage = "Song-of-the-Sea-1.jpg";
+  # stylixImage = "Wolfwalkers-1.jpg";
+  # stylixImage = "Wolfwalkers-2.jpg";
 
   # Set network hostId if required (needed for zfs)
   # Otherwise leave as-is