feat(demo): add story 1 — Sorano: Rock and Time

plugins/api/classes/Api/Exceptions/ValidationException.php

@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Grav\Plugin\Api\Exceptions;
+
+class ValidationException extends ApiException
+{
+    public function __construct(
+        string $detail = 'The request data is invalid.',
+        protected readonly array $errors = [],
+        ?\Throwable $previous = null,
+    ) {
+        parent::__construct(422, 'Unprocessable Entity', $detail, [], $previous);
+    }
+
+    public function getValidationErrors(): array
+    {
+        return $this->errors;
+    }
+}