TorchPlugin.catopiarex.Sclean 1.0.0

Works on grid groups rather than single grids, so one failing subgrid does not condemn the rest: a group is kept when any grid in it satisfies a requirement, which lets it find rovers carrying a Beacon. A group survives when it is player-owned and powered and lies inside the safe zone of the player or the Scrap Beacon, with the zone ranges configurable.