feat: implement premium Email 2FA authentication integrated with auth flow

app/Mail/Send2FACode.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace App\Mail;
+
+use Illuminate\Bus\Queueable;
+use Illuminate\Mail\Mailable;
+use Illuminate\Mail\Mailables\Content;
+use Illuminate\Mail\Mailables\Envelope;
+use Illuminate\Queue\SerializesModels;
+
+class Send2FACode extends Mailable
+{
+    use Queueable, SerializesModels;
+
+    public string $code;
+
+    public function __construct(string $code)
+    {
+        $this->code = $code;
+    }
+
+    public function envelope(): Envelope
+    {
+        return new Envelope(
+            subject: '[' . config('app.name') . '] Two-Factor Authentication Code',
+        );
+    }
+
+    public function content(): Content
+    {
+        return new Content(
+            markdown: 'emails.two-factor-code',
+        );
+    }
+}