Add nixos options.

nodes/hosts/common/configuration.nix

@@ -24,20 +24,9 @@
     ./system/bluetooth.nix
     ./system/environment.nix
     ./system/locale.nix
+    ./system/nixos.nix
     ./system/security.nix
     ./system/time.nix
     ./system/users.nix
   ];
-
-  nixpkgs = {
-    config.allowUnfree = true;
-  };
-
-  nix = {
-    gc.options = "--delete-older-than 30d";
-    optimise.automatic = true;
-    extraOptions = ''
-      experimental-features = nix-command flakes
-    '';
-  };
 }

nodes/hosts/common/system/nixos.nix

@@ -0,0 +1,16 @@
+{ ... }: {
+  nix = {
+    gc.options = "--delete-older-than 30d";
+    optimise.automatic = true;
+    settings = {
+      experimental-features = [ "nix-command" "flakes" ];
+      substituters = ["https://hyprland.cachix.org"];
+      trusted-public-keys = ["hyprland.cachix.org-1:a7pgxzMz7+chwVL3/pzj6jIBMioiJM7ypFP8PwtkuGc="];
+    };
+  };
+
+  # Allow unfree packages
+  nixpkgs.config.allowUnfree = true;
+
+  zramSwap.enable = true;
+}