make stateversion actually do something

lib.nix

@@ -101,6 +101,9 @@ let
                 nixpkgs.config = mergedNixpkgsConfig;
                 nixpkgs.overlays = mergedOverlays;
               }
+              {
+                system.stateVersion = stateVersion;
+              }
             ]
             ++ nixosModules;
           };
@@ -116,7 +119,7 @@ let
             extraSpecialArgs = extraArgs // {
               inherit system user;
             };
-            modules = homeModules;
+            modules = [ { home.stateVersion = stateVersion; } ] ++ homeModules;
           };
         };
       in