Fix (Royalty) transport ships

Currently, sending a transport ships in some circumstances (like summoning one through royal permits) would result in them disappearing with all pawns and items they carry when arriving at their destinations.

The issue was caused due to transport ships themselves not being registered in shared cross refs, which caused them to fail syncing them as IExposable.

Source/Client/Saving/CrossRefs.cs

@@ -301,4 +301,37 @@ static void Postfix(ThingOwner __instance)
             }
         }
     }
+
+    [HarmonyPatch(typeof(TransportShipManager), nameof(TransportShipManager.RegisterShipObject))]
+    public static class TransportShipAddPatch
+    {
+        public static void Postfix(TransportShip s)
+        {
+            if (Multiplayer.game == null) return;
+            ScribeUtil.sharedCrossRefs.RegisterLoaded(s);
+        }
+    }
+
+    [HarmonyPatch(typeof(TransportShipManager), nameof(TransportShipManager.DeregisterShipObject))]
+    public static class TransportShipRemovePatch
+    {
+        public static void Postfix(TransportShip s)
+        {
+            if (Multiplayer.game == null) return;
+            ScribeUtil.sharedCrossRefs.Unregister(s);
+        }
+    }
+
+    [HarmonyPatch(typeof(TransportShipManager), nameof(TransportShipManager.ExposeData))]
+    public static class TransportShipExposePatch
+    {
+        static void Postfix(TransportShipManager __instance)
+        {
+            if (Multiplayer.game == null) return;
+
+            if (Scribe.mode == LoadSaveMode.PostLoadInit)
+                foreach (var ship in __instance.ships)
+                    ScribeUtil.sharedCrossRefs.RegisterLoaded(ship);
+        }
+    }
 }