treewide: set allowUnfree for flake

flake.nix

@@ -42,8 +42,13 @@
       ];
 
       perSystem =
-        { pkgs, ... }:
+        { pkgs, system, ... }:
         {
+          _module.args.pkgs = import inputs.nixpkgs {
+            inherit system;
+            config.allowUnfree = true;
+          };
+
           formatter = pkgs.nixfmt;
         };
 

nixos/common.nix

@@ -118,10 +118,10 @@ in
 
   nixpkgs.config.allowUnfree = true;
 
-  environment.etc."nixos/current".source = lib.cleanSource ./..;
-
   system = {
     configurationRevision = self.rev or self.dirtyRev;
     stateVersion = "25.11";
   };
+
+  environment.etc."nixos/current".source = lib.cleanSource ./..;
 }