feat: Add Laravel tinker examples and update nominal accounts functionality

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

src/Traits/SignableData.php

@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Apoloz\AlfaBank\Traits;
+
+use Apoloz\AlfaBank\Contracts\SignerInterface;
+use Apoloz\AlfaBank\Data\NominalAccounts\Payouts\DigestSignatureData;
+use Spatie\LaravelData\DataCollection;
+
+trait SignableData
+{
+    public function sign(SignerInterface $signer): self
+    {
+        // 1. Create a clone to represent the data-to-be-signed (without existing signatures)
+        $clone = clone $this;
+        
+        // We explicitly set digestSignatures to null or empty for the signature calculation
+        // assuming the bank expects the "business payload" only.
+        // If the bank expects the field "digestSignatures": [] to be present in signed string,
+        // we should initialize it as empty collection.
+        // Based on common practices, we exclude it or keep it null.
+        // Let's assume we exclude it (set to null if the property is nullable).
+        $clone->digestSignatures = null;
+
+        // 2. Serialize to JSON
+        // We use JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES to match typical API expectations
+        $jsonToSign = $clone->toJson(JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
+
+        // 3. Sign
+        $signature = $signer->sign($jsonToSign);
+
+        // 4. Attach signature to the original object
+        if ($this->digestSignatures === null) {
+            $this->digestSignatures = new DataCollection(DigestSignatureData::class, []);
+        }
+
+        // We can't push to DataCollection directly if it's not array-access compatible in all versions,
+        // but Spatie DataCollection is usually iterable.
+        // Safest way is to reconstruct it.
+        $current = $this->digestSignatures->toCollection()->all();
+        $current[] = new DigestSignatureData($signature, 'cms');
+        
+        $this->digestSignatures = new DataCollection(DigestSignatureData::class, $current);
+
+        return $this;
+    }
+}