Ship orders: shipments with delivery notes

$order->shipments()->create([...]) records a delivery of a paid order's goods on Anikeen ID,
which adds its delivery note to the user's order documents and sends order.shipped.
$shipment->deliveryNote() downloads the PDF.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/Id/Resources/Shipment.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace Anikeen\Id\Resources;
+
+use Anikeen\Id\Concerns\HasBillable;
+use Anikeen\Id\Concerns\HasParent;
+use Throwable;
+
+/**
+ * @property string $id
+ * @property string $number delivery note number, e.g. LS-2026-0001
+ * @property string $order_id
+ * @property null|string $carrier
+ * @property null|string $tracking_number
+ * @property null|string $tracking_url
+ * @property array $items order_item_id, name, description, units
+ * @property object $shipping_address
+ * @property null|string $note
+ * @property string $shipped_at
+ */
+class Shipment extends BaseResource
+{
+    use HasBillable;
+    use HasParent;
+
+    /**
+     * The delivery note as PDF (binary string).
+     *
+     * @throws Throwable
+     */
+    public function deliveryNote(): string
+    {
+        $result = $this->billable->anikeenId()
+            ->request('GET', sprintf('v1/orders/%s/shipments/%s/delivery-note', $this->order_id, $this->id));
+
+        return (string) $result->response?->getBody();
+    }
+}