feat: full mail server — send + receive for @csrx.ru
Upgrade docker-mailserver from SMTP_ONLY to full Postfix + Dovecot:
- Remove SMTP_ONLY, enable Dovecot (IMAP) and Rspamd (spam filter)
- Expose ports 25 (SMTP), 587 (submission), 993 (IMAPS), 465 (SMTPS)
- SSL_TYPE=letsencrypt — certbot obtains cert for mail.csrx.ru via
Cloudflare DNS-01 challenge (uses existing cloudflare_dns_api_token)
- UFW: open ports 25, 587, 993, 465
- Accounts: admin@csrx.ru, jack@csrx.ru, noreply@csrx.ru
Mail client settings after deploy:
IMAP: mail.csrx.ru:993 (SSL)
SMTP: mail.csrx.ru:587 (STARTTLS)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>