Configure email, push notification, and SMS delivery settings.
Mailtrap SMTP Configuration
Use live.smtp.mailtrap.io for production sending.
Port 587 (recommended) with STARTTLS.
AWS SES SMTP Configuration
Use region-specific SMTP endpoint: email-smtp.<region>.amazonaws.com
(e.g., email-smtp.us-east-1.amazonaws.com). Port 587 with STARTTLS.