feat: first impl

src/StdioPiped.php

@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nih\CommandBuilder;
+
+final class StdioPiped extends Stdio
+{
+    public function __construct(public readonly string $mode)
+    {}
+
+    public function getDescriptorSpec(): array
+    {
+        return ['pipe', $this->mode];
+    }
+}