refactor: flake dir -> outputs/sys -> nixos

nixos/modules/base/boot/plymouth.nix

@@ -0,0 +1,18 @@
+{ lib, config, pkgs, ... }:
+
+let
+  inherit (lib) mkIf mkEnableOption;
+  cfg = config.sys.boot.plymouth;
+in
+
+{
+  options.sys.boot.plymouth.enable = mkEnableOption "";
+
+  config = mkIf cfg.enable {
+    boot.plymouth = {
+      enable = true;
+      themePackages = [(pkgs.catppuccin-plymouth.override {variant = "mocha";})];
+      theme = "catppuccin-mocha";
+    };
+  };
+}