Description

Add a reusable email server stack/template based on Docker Mailserver for issue #8266.

Changes

• Added docker-mailserver.yaml template
• Supports SMTP (25, 587), IMAPS (993)
• Persistent volumes for mail, state, logs

Demo

Verification

• YAML syntax validated
• Follows Coolify template format
• Template will appear in Coolify services after merge

/claim #8266