depend on the registry instead of DebrisSystem in the AI path

src/test/BehaviorSystemTest.cpp

@@ -101,14 +101,14 @@ struct Fixture
     void decide()
     {
         ships.clearMovementIntents();
-        ai.tick(admin, state, scraps);
+        ai.tick(admin, state);
     }
 
     // World mutation: collection/delivery and healing.
     void runModules()
     {
         beamEvents.clear();
-        salvager.tick(tick, scraps, state, beamEvents);
+        salvager.tick(tick, state, beamEvents);
         repair.tick(tick, beamEvents);
     }
 
@@ -141,7 +141,7 @@ struct Fixture
     void salvageTick()
     {
         beamEvents.clear();
-        salvager.tick(tick, scraps, state, beamEvents);
+        salvager.tick(tick, state, beamEvents);
         ++tick;
     }