fix: reduce snapshot payloads via serializer group and hydration

migrations/Version20260324120000.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Changes travel_snapshot.payload from TEXT to LONGTEXT so large
+ * plain JSON snapshot payloads can be stored safely.
+ */
+final class Version20260324120000 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Change travel_snapshot.payload from TEXT to LONGTEXT for plain JSON snapshot payloads';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE travel_snapshot CHANGE payload payload LONGTEXT NOT NULL');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE travel_snapshot CHANGE payload payload TEXT NOT NULL');
+    }
+}