some minor fixes

hosts/toothpc/default.nix

@@ -35,6 +35,8 @@ in {
     ./modules.nix
   ];
 
+  environment.variables.FLAKE = "/home/toothpick/.nix-config";
+
   # https://nixos.wiki/wiki/FAQ/When_do_I_update_stateVersion
   system.stateVersion = lib.mkDefault "23.11";
 }

hosts/toothpc/modules.nix

@@ -67,6 +67,15 @@
         };
       };
     };
+    nix = {
+      nh = {
+        enable = true;
+        clean = {
+          enable = true;
+          extraArgs = "--keep 3 --keep-since 21d";
+        };
+      };
+    };
     studio = {
       blender = {
         enable = false;