SitePlannerSession
class SitePlannerSession(val nodeNum: Int?, val mapCenter: () -> Position, val moveTo: (Position) -> Unit, val onDismiss: () -> Unit)(source)
A Site Planner session the map is asking its host to run.
Host-supplied for the same reason as the waypoint editor: the planner itself lives in the app, not in this module, and it has no desktop host. A host that supplies nothing gets no Site Planner button at all.