Add RemoveRoute, RemoveAllRoutesExcept, RegisterRoute (internal), and DetectClusterSplit to RouteManager with ClusterSplitResult record, plus 10 tests covering partition detection and route removal behavior.
Add RemoveRoute, RemoveAllRoutesExcept, RegisterRoute (internal), and DetectClusterSplit to RouteManager with ClusterSplitResult record, plus 10 tests covering partition detection and route removal behavior.