- mail/mail.service.ts: MailService with HTML templates (welcome, submitted, approved, rejected, pending, deactivated). Silent if SMTP not configured. - mail/mail.module.ts: global module so all services can inject MailService - auth.service.ts: send welcome email on register() - professionals.service.ts: notify admin on new submission; notify professional on approve/deny/deactivate/setPending Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>