Add audit system core with event handling and subject conversion

- Implemented `AuditEvent` class to represent audit events.
- Added `AuditEvent2Trail` for converting events to audit trails.
- Introduced `Subject` and `SubjectConverterManager` for subject conversion.
- Created contracts like `SubjectConverterInterface` and `AuditEvent2TrailInterface`.
- Developed `AuditEventSubscriber` to persist audit events using `AuditTrailPersister`.
- Included test classes for core audit services and components.

src/Bundle/ChillMainBundle/Audit/SubjectConverterManager.php

@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Chill\MainBundle\Audit;
+
+use Chill\MainBundle\Audit\Exception\ConvertSubjectException;
+
+final readonly class SubjectConverterManager implements SubjectConverterManagerInterface
+{
+    public function __construct(
+        /**
+         * @var iterable<SubjectConverterInterface>
+         */
+        private iterable $converters,
+    ) {}
+
+    /**
+     * @return list<array>
+     *
+     * @throws ConvertSubjectException
+     */
+    public function convertEntityToSubjects(mixed $subject): array
+    {
+        foreach ($this->converters as $converter) {
+            if ($converter->supportsConvert($subject)) {
+                $subjects = $converter->convert($subject);
+
+                if ($subjects instanceof Subject) {
+                    return [$subjects->asArray()];
+                }
+
+                return array_map(static fn (Subject $subject) => $subject->asArray(), $subjects);
+            }
+        }
+
+        throw new ConvertSubjectException($subject);
+    }
+}