Z-Push ActiveSync container for iOS/Android/Outlook native sync

[deeztek]

Summary

Add Z-Push as a Docker container to provide native ActiveSync (Microsoft EAS) support for mobile devices and Outlook, alongside the existing Nextcloud webmail.

Architecture

• New container: hermes_zpush (lightweight, Ubuntu-based)
• IMAP backend: connects to hermes_dovecot for email
• CalDAV/CardDAV backend: connects to NC's /nc/remote.php/dav/ for calendar/contacts
• Auth: LDAP (same credentials as email)
• Nginx: /Microsoft-Server-ActiveSync → hermes_zpush

Why Z-Push

• Open-source ActiveSync implementation (EAS protocol)
• Mature, well-documented, used by major open-source email platforms
• Works alongside NC without replacing it
• Each component does what it's best at: NC for webmail/files, Z-Push for native mobile sync

Alternative considered

• SOGo: Has native ActiveSync but would replace NC entirely. Could coexist at a different path but adds more complexity than Z-Push for just the ActiveSync feature.