Fix transfer recipient emails not sending in production.

Map MAIL_ENCRYPTION to a valid SMTP scheme, send recipient notifications
synchronously, document mail/queue env vars, and add a supervisor worker template.

Co-authored-by: Cursor <cursoragent@cursor.com>

config/mail.php

@@ -1,5 +1,16 @@
 <?php
 
+$mailScheme = strtolower(trim((string) env('MAIL_SCHEME', '')));
+$mailEncryption = strtolower(trim((string) env('MAIL_ENCRYPTION', '')));
+
+$smtpScheme = match (true) {
+    in_array($mailScheme, ['smtp', 'smtps'], true) => $mailScheme,
+    $mailScheme !== '' => null,
+    in_array($mailEncryption, ['ssl', 'smtps'], true) => 'smtps',
+    in_array($mailEncryption, ['tls', 'starttls', 'smtp'], true) => 'smtp',
+    default => null,
+};
+
 return [
 
     /*
@@ -39,7 +50,7 @@ return [
 
         'smtp' => [
             'transport' => 'smtp',
-            'scheme' => env('MAIL_SCHEME'),
+            'scheme' => $smtpScheme,
             'url' => env('MAIL_URL'),
             'host' => env('MAIL_HOST', '127.0.0.1'),
             'port' => env('MAIL_PORT', 2525),