feat: MailJet list handling with DOI, webhook receiver and API endpoint

addresses #869cut134

migrations/Version20260422120000.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+final class Version20260422120000 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Store requested Mailjet list IDs on newsletter opt-in confirmations';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql("ALTER TABLE newsletter_opt_in_confirmation ADD mailjet_list_ids JSON DEFAULT NULL COMMENT '(DC2Type:json)'");
+        $this->addSql('UPDATE newsletter_opt_in_confirmation SET mailjet_list_ids = JSON_ARRAY(10321569) WHERE mailjet_list_ids IS NULL');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE newsletter_opt_in_confirmation DROP mailjet_list_ids');
+    }
+}