add server1 and change flatpak to make it works if not defined

flake.nix

@@ -42,6 +42,15 @@
             nvf.nixosModules.default
           ];
         };
+        server1 = nixpkgs.lib.nixosSystem {
+          specialArgs = { inherit inputs system overlays; };
+          modules = [
+            ./hosts/server1/configuration.nix
+            nix-flatpak.nixosModules.nix-flatpak
+            inputs.stylix.nixosModules.stylix
+            nvf.nixosModules.default
+          ];
+        };
         laptop1 = nixpkgs.lib.nixosSystem {
           specialArgs = { inherit inputs system overlays; };
           modules = [