implement find by email in fake user repo

tests/Fakes/FakeUserRepository.php

@@ -5,6 +5,7 @@ namespace Tests\Fakes;
 use App\User\UseCases\CreateUserDto;
 use App\User\User;
 use App\User\UserRepository;
+use App\ValueObjects\EmailAddress;
 
 class FakeUserRepository implements UserRepository
 {
@@ -32,6 +33,25 @@ class FakeUserRepository implements UserRepository
         );
     }
 
+    public function findByEmail(EmailAddress $email): ?User
+    {
+        $user = array_find(
+            $this->existingUsers,
+            function (User $user) use ($email) {
+                return (string) $user->getEmail() === (string) $email;
+            }
+        );
+        if ($user === null) {
+            return null;
+        }
+
+        return new User(
+            id: $user->getId(),
+            email: $user->getEmail(),
+            isAdmin: $user->isAdmin(),
+        );
+    }
+
     public function create(CreateUserDto $dto): User
     {
         $id = $this->nextId();