feat: first impl

src/Output.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nih\CommandBuilder;
+
+final class Output
+{
+    public function __construct(
+        public readonly ?string $stdout,
+        public readonly ?string $stderr,
+        public readonly int $code,
+    ) {
+    }
+}