Add start of Document class

src/Document.php

@@ -0,0 +1,18 @@
+<?php declare(strict_types=1);
+
+namespace Aviat\Kilo;
+
+class Document {
+	private function __construct(
+		public array $rows = [],
+		public ?string $filename = NULL,
+		private bool $dirty = FALSE,
+	) {}
+
+	public static function open(?string $filename = NULL): self
+	{
+		// @TODO move logic from Editor
+		return new self(filename: $filename);
+	}
+
+}