fix issue where status light was flickering to yellow for one tick between cycles

src/lib/sim/ProductionRules.h

@@ -53,6 +53,16 @@ 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 a production cycle could actually start right now: some candidate recipe
+// has its inputs *and* its output fits (REQ-MAT-CYCLE). Stricter than
+// hasInputsToStart, which looks at the input buffers alone.
+bool canStartCycle(const GameConfig& config, const Building& b);
+
 // Status light for a building, or nullopt for types that show none — belts,
 // splitters, tunnels, HQ and defence stations (REQ-UI-STATUS-LIGHT).
 std::optional<ProductionStatus> getProductionStatus(const GameConfig& config,