perhaps one step removed from fleet separation mechanics, but this one should be a bit simpler to implement (if a bit more limited)
since we can already leave cargo to come back to later, I propose we be allowed to do the same for ships. A ship dropped off in space can be tracked permanently and will need to be supplied and crewed to maintain CR, otherwise it will lose CR as though it's unsupplied and mothball itself once CR reaches 0. Ships left in space will be subject to all terrain (nebula/asteroid belts, mostly) and will be running dark. Enemy fleets will not look for the ship unless they see you drop it or have seen your fleet recently (and therefore identify the fleet as missing a juicy freighter, for example). If they find the ship they will destroy/capture/loot it but if they're not specifically looking for it they will not interact with it in any way.
