feat: entité Domain liée à Customer avec migration

Entity Domain :
- customer (ManyToOne, CASCADE) : client propriétaire du domaine
- fqdn (unique) : nom de domaine complet, lowercase auto
- registrar : bureau d'enregistrement (OVH, Gandi, etc.)
- zoneCloudflare : statut zone Cloudflare (active, pending, etc.)
- zoneIdCloudflare : identifiant zone Cloudflare
- expiredAt : date d'expiration du domaine
- isGestion : domaine géré par SITECONSEIL
- isBilling : domaine facturé par SITECONSEIL
- createdAt / updatedAt : timestamps
- isExpired() : vérifie si le domaine est expiré
- isExpiringSoon(days) : vérifie si expiration dans les N jours

DomainTest (4 tests, 25 assertions) :
- testConstructor : valeurs par défaut, fqdn lowercase/trim
- testSetters : tous les setters/getters
- testIsExpired : null/passé/futur
- testIsExpiringSoon : null/15j (true pour 30j)/60j (false pour 30j)

Migration : CREATE TABLE domain avec FK customer ON DELETE CASCADE

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

migrations/Version20260403220210.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * Auto-generated Migration: Please modify to your needs!
+ */
+final class Version20260403220210 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return '';
+    }
+
+    public function up(Schema $schema): void
+    {
+        // this up() migration is auto-generated, please modify it to your needs
+        $this->addSql('CREATE TABLE domain (id INT GENERATED BY DEFAULT AS IDENTITY NOT NULL, fqdn VARCHAR(255) NOT NULL, registrar VARCHAR(255) DEFAULT NULL, zone_cloudflare VARCHAR(50) DEFAULT NULL, zone_id_cloudflare VARCHAR(100) DEFAULT NULL, expired_at TIMESTAMP(0) WITHOUT TIME ZONE DEFAULT NULL, is_gestion BOOLEAN NOT NULL, is_billing BOOLEAN NOT NULL, created_at TIMESTAMP(0) WITHOUT TIME ZONE NOT NULL, updated_at TIMESTAMP(0) WITHOUT TIME ZONE DEFAULT NULL, customer_id INT NOT NULL, PRIMARY KEY (id))');
+        $this->addSql('CREATE UNIQUE INDEX UNIQ_A7A91E0BC1A19758 ON domain (fqdn)');
+        $this->addSql('CREATE INDEX IDX_A7A91E0B9395C3F3 ON domain (customer_id)');
+        $this->addSql('ALTER TABLE domain ADD CONSTRAINT FK_A7A91E0B9395C3F3 FOREIGN KEY (customer_id) REFERENCES customer (id) ON DELETE CASCADE NOT DEFERRABLE');
+    }
+
+    public function down(Schema $schema): void
+    {
+        // this down() migration is auto-generated, please modify it to your needs
+        $this->addSql('ALTER TABLE domain DROP CONSTRAINT FK_A7A91E0B9395C3F3');
+        $this->addSql('DROP TABLE domain');
+    }
+}