Fixed/Unfixed Toggle to Exclude Devices and Groups from Map Layout Changes

NetBrain currently has no position-locking mechanism for individual devices or groups on a map; all elements remain subject to layout changes made elsewhere on the map, including changes triggered by configuration drift. This enhancement would add a toggle to mark selected devices or groups as fixed or unfixed, so that fixed elements retain their position and are excluded from layout changes applied elsewhere on the map. Customers maintaining large or frequently updated topologies would benefit from being able to preserve intentional placement of key devices or groups while still allowing automated layout adjustments to occur across the rest of the map.