Set default wallpaper to Attack-on-Titan-2

- Updated host variables files to select Attack-on-Titan-2.jpg and added
  rating comments.
- Simplified boot.nix by removing host‑specific imports and configuring
  limine via package, resolution, and branding color.
- Added limine target support in stylix with color, image, and tile
  scaling options.
- Removed the unused noctalia colors module and its import.
- Adjusted noctalia wallpaper settings to use config.stylix.image
  instead of a host import.

modules/home/noctalia/settings/wallpapers.nix

@@ -1,11 +1,9 @@
 {
   lib,
-  host,
+  config,
   username,
   ...
-}: let
-  inherit (import ../../../../hosts/${host}/variables.nix) stylixImage;
-in {
+}: {
   programs.noctalia-shell.settings.wallpaper = lib.mkForce {
     enabled = true;
     overviewEnabled = false;
@@ -42,6 +40,6 @@ in {
   };
 
   home.file.".cache/noctalia/wallpapers.json".text = lib.mkForce (builtins.toJSON {
-    defaultWallpaper = ../../../../wallpapers/${stylixImage};
+    defaultWallpaper = config.stylix.image;
   });
 }