v0.43.0

Added

• Automatic scheduled backups: database backups are now created automatically on a configurable cron schedule (default: 2 AM daily). Old backups are rotated automatically, keeping only the last N copies (default: 7). Configuration via .env variables: BACKUP_ENABLED, BACKUP_SCHEDULE, BACKUP_DIR, BACKUP_KEEP. Settings → Backup displays scheduler status, schedule, retention policy, last backup timestamp, and a manual trigger button.