fix: added runtime

flake.nix

@@ -70,7 +70,21 @@
             dontFixup = true;
           };
 
-          default = hexname-frontend;
+          runtime = pkgs.writeShellApplication {
+            name = pname;
+
+            runtimeInputs = [
+              pkgs.nodejs
+            ];
+
+            text = ''
+              export NODE_ENV=production
+              exec node ${site}/build/index.js
+            '';
+          };
+
+          # default = hexname-frontend;
+          default = runtime;
         };
 
         devShells.default = pkgs.mkShell {