Refactor(Auth): Complete auth folder restructuring, security patches, and Flutter endpoint updates

backend/auth/passenger/remove_account.php

@@ -0,0 +1,30 @@
+<?php
+require_once __DIR__ . '/../connect.php';
+
+$email = filterRequest("email");
+
+$headers = "MIME-Version: 1.0" . "\r\n";
+$headers .= "Content-type: text/html; charset=UTF-8" . "\r\n";
+$headers .= "From: SEFER Team" . "\r\n";
+
+// Create the email subject and body
+$subject = 'Your SEFER account has been deleted';
+$body = '
+
+Dear passenger,
+
+We are sorry to see you go, but we respect your decision to delete your SEFER account.
+
+We would like to thank you for using our platform and for being a part of the SEFER community. We hope that you had a positive experience and that we were able to make your travels easier and more enjoyable.
+
+If you have any questions or concerns, please do not hesitate to contact us.
+
+Sincerely,
+
+The SEFER Team
+';
+
+// Send the email
+mail($email, $subject, $body);
+
+?>