allow the probabilistic recipe output of the reprocessing plant to yield more than 1 item of a type per cycle

src/test/BehaviorSystemTest.cpp

@@ -1000,8 +1000,9 @@ TEST_CASE("SalvagerSystem: full-cargo ship at its SalvageBay hands over cargo",
     }
     const Building* bay = findBuilding(f.state, bayId);
     REQUIRE(bay != nullptr);
-    // Config-driven output-buffer capacity is applied on placement (REQ-BLD-SALVAGE-BAY).
-    REQUIRE(bay->outputBuffer.capacity == 20);
+    // Config-driven output-buffer capacity is applied on placement, onto the single
+    // scrap buffer the bay holds (REQ-BLD-SALVAGE-BAY).
+    REQUIRE(bay->outputBuffer.caps.at(ItemType{"scrap"}) == 20);
 
     const QVector2D bayCenter(bay->anchor.x() + bay->footprint.width()  / 2.0f,
                               bay->anchor.y() + bay->footprint.height() / 2.0f);