# A single exploration frontier cell cluster.

string                  frontier_id      # unique ID: "<robot_id>_<seq>"
geometry_msgs/Point     centroid         # in fleet common frame
float32                 area_m2          # approximate size of frontier cluster
float32                 utility          # combined score (size × 1/distance)
string                  assigned_to      # robot_id if claimed, "" if open
builtin_interfaces/Time assigned_at
