add email signup flow

backend/app/Email/LaravelEmailer.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace App\Email;
+
+use App\Shared\ValueObject\EmailAddress;
+use Illuminate\Contracts\Mail\Mailer;
+use Illuminate\Mail\Message;
+
+class LaravelEmailer implements Emailer
+{
+    public function __construct(private Mailer $mailer) {}
+
+    public function send(
+        EmailAddress $recipient,
+        string $subject,
+        string $body,
+    ): void {
+        $this->mailer->raw(
+            $body,
+            function (Message $message) use ($recipient, $subject): void {
+                $message->to($recipient->value())->subject($subject);
+            },
+        );
+    }
+}