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

src/lib/sim/ProductionRules.h

@@ -53,13 +53,21 @@ double computeShipyardProductionTimeSeconds(
 // True when a production cycle could start right now, ignoring output-buffer space.
 bool hasInputsToStart(const GameConfig& config, const Building& b);
 
-// True when the building's output side can take `outputItemCount` more items beside
-// what it already holds. An emerging item has not left the building yet and so still
-// counts against the capacity (REQ-MAT-OUTPUT-EMERGE, REQ-MAT-OUTPUT-BUFFER).
-bool outputBufferHasRoom(const Building& b, int outputItemCount);
+// True when the building can take `itemCount` more items of `type` beside what it
+// already holds of it. An emerging item has not left the building yet and so still
+// counts against that material's capacity (REQ-MAT-OUTPUT-EMERGE, REQ-MAT-OUTPUT-BUFFER).
+bool outputBufferHasRoom(const Building& b, const ItemType& type, int itemCount);
+
+// True when every output a cycle of this recipe could produce would fit -- the gate a
+// cycle has to pass before it may start (REQ-MAT-CYCLE). For a deterministic recipe that
+// is its own outputs. A Reprocessing Plant rolls one of its outputs per cycle
+// (REQ-BLD-REPROCESSING), so each possibility is judged on its own and all must fit: the
+// roll is committed the moment the cycle starts, and testing every outcome rather than
+// the rolled one is what keeps a stalled output belt from biasing the distribution.
+bool recipeOutputsFit(const Building& b, const RecipeDef& recipe);
 
 // True when a production cycle could actually start right now: some candidate recipe
-// has its inputs *and* its output fits (REQ-MAT-CYCLE). Stricter than
+// has its inputs *and* passes recipeOutputsFit (REQ-MAT-CYCLE). Stricter than
 // hasInputsToStart, which looks at the input buffers alone.
 bool canStartCycle(const GameConfig& config, const Building& b);