Based on PR #135 by @andreibrebene with adjustments:
- TZ environment variable for Docker timezone support
- Granular auto-backup schedule (hour, day of week, day of month)
- UTC timestamp fix for admin panel
- Server timezone exposed in app-config API
- Replaced native selects with CustomSelect for consistent UI
- Backup schedule UI with 12h/24h time format support
Thanks @andreibrebene for the implementation!