Now that Resend.com supports sending email via SMTP, we should convert the webapp to use a native SMTP mailer instead of the Resend SDK. We will need to replace the RESEND_API_KEY with SMTP_* environment variables (which should still be optional). When SMTP_* env vars are missing, we should continue to print the Magic Link login emails to the console how we are currently doing.

This will allow self-hosters to send email* without having to sign up to Resend.com and possibly use an existing email provider.

• Currently only used for Magic Link login

_TRI-951