Add nixpacks configuration and update package manager to pnpm

nixpacks.toml

@@ -0,0 +1,5 @@
+[phases.setup]
+nixPkgs = ["nodejs_22", "pnpm"]
+
+[variables]
+NODE_VERSION = "22"

package.json

@@ -36,5 +36,6 @@
 	},
 	"dependencies": {
 		"parse-domain": "^8.2.2"
-	}
+	},
+	"packageManager": "pnpm@latest"
 }