Scheduled Maintenance Mode to Suspend Live Access for Selected Devices

NetBrain currently has no mechanism to suspend live access to specific devices during planned maintenance windows, which can result in failed access attempts, false alerts, or interference with ongoing maintenance work. This enhancement would allow administrators to place one or more devices into a Maintenance Mode with a configurable start and end datetime. While a device is within its maintenance window, NetBrain would skip all live access to that device, including scheduled discovery, on-demand CLI, path diagnosis, and runbook execution, then automatically resume normal access once the window expires. Customers performing scheduled device maintenance would benefit from reduced false alerts and fewer disruptions to maintenance activities, along with the convenience of automatic access resumption without manual intervention.