refactor: move ark into dentritic pattern

modules/koon/host/ark/default.nix

@@ -0,0 +1,8 @@
+{ self, inputs, ... }: {
+  flake.nixosConfigurations.koonArk = inputs.nixpkgs-unstable.lib.nixosSystem {
+    modules = [
+      self.inputs.sops-nix.nixosModules.sops
+      self.nixosModules.koonArkConfiguration
+    ];
+  };
+}