feat: entité CustomerContact pour contacts additionnels d'un client

Entity CustomerContact :
- customer (ManyToOne, CASCADE) : client parent
- firstName, lastName : nom/prénom du contact
- email : adresse email (nullable)
- phone : téléphone (nullable)
- role : fonction dans l'entreprise (Gérant, Comptable, etc.)
- isBillingEmail : si true, reçoit les factures par email
- createdAt / updatedAt : timestamps
- getFullName() : prénom + nom

CustomerContactTest (2 tests, 19 assertions) :
- testConstructor : valeurs par défaut
- testSetters : tous les setters/getters

Migration : CREATE TABLE customer_contact avec FK customer ON DELETE CASCADE

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

tests/Entity/CustomerContactTest.php

@@ -0,0 +1,68 @@
+<?php
+
+namespace App\Tests\Entity;
+
+use App\Entity\Customer;
+use App\Entity\CustomerContact;
+use App\Entity\User;
+use PHPUnit\Framework\TestCase;
+
+class CustomerContactTest extends TestCase
+{
+    private function createCustomer(): Customer
+    {
+        $user = new User();
+        $user->setEmail('c@t.com');
+        $user->setFirstName('C');
+        $user->setLastName('T');
+        $user->setPassword('h');
+
+        return new Customer($user);
+    }
+
+    public function testConstructor(): void
+    {
+        $customer = $this->createCustomer();
+        $contact = new CustomerContact($customer, 'Jean', 'Dupont');
+
+        $this->assertNull($contact->getId());
+        $this->assertSame($customer, $contact->getCustomer());
+        $this->assertSame('Jean', $contact->getFirstName());
+        $this->assertSame('Dupont', $contact->getLastName());
+        $this->assertSame('Jean Dupont', $contact->getFullName());
+        $this->assertNull($contact->getEmail());
+        $this->assertNull($contact->getPhone());
+        $this->assertNull($contact->getRole());
+        $this->assertFalse($contact->isBillingEmail());
+        $this->assertInstanceOf(\DateTimeImmutable::class, $contact->getCreatedAt());
+        $this->assertNull($contact->getUpdatedAt());
+    }
+
+    public function testSetters(): void
+    {
+        $contact = new CustomerContact($this->createCustomer(), 'A', 'B');
+
+        $contact->setFirstName('Marie');
+        $this->assertSame('Marie', $contact->getFirstName());
+
+        $contact->setLastName('Martin');
+        $this->assertSame('Martin', $contact->getLastName());
+        $this->assertSame('Marie Martin', $contact->getFullName());
+
+        $contact->setEmail('marie@entreprise.fr');
+        $this->assertSame('marie@entreprise.fr', $contact->getEmail());
+
+        $contact->setPhone('0612345678');
+        $this->assertSame('0612345678', $contact->getPhone());
+
+        $contact->setRole('Comptable');
+        $this->assertSame('Comptable', $contact->getRole());
+
+        $contact->setIsBillingEmail(true);
+        $this->assertTrue($contact->isBillingEmail());
+
+        $now = new \DateTimeImmutable();
+        $contact->setUpdatedAt($now);
+        $this->assertSame($now, $contact->getUpdatedAt());
+    }
+}