start (actual) email auth, add CancellationToken to most async methods

Foxnouns.Backend/Services/MailService.cs

@@ -0,0 +1,24 @@
+using Coravel.Mailer.Mail.Interfaces;
+using Coravel.Queuing.Interfaces;
+using Foxnouns.Backend.Mailables;
+
+namespace Foxnouns.Backend.Services;
+
+public class MailService(ILogger logger, IMailer mailer, IQueue queue, Config config)
+{
+    private readonly ILogger _logger = logger.ForContext<MailService>();
+
+    public void QueueAccountCreationEmail(string to, string code)
+    {
+        _logger.Debug("Sending account creation email to {ToEmail}", to);
+        
+        queue.QueueAsyncTask(async () =>
+        {
+            await mailer.SendAsync(new AccountCreationMailable(config, new AccountCreationMailableView
+            {
+                To = to,
+                Code = code
+            }));
+        });
+    }
+}