Derive ship scrap drop from threat

src/lib/sim/ThreatCostCalculator.cpp

@@ -1,6 +1,5 @@
 #include "ThreatCostCalculator.h"
 
-#include <limits>
 #include <set>
 
 #include "GameConfig.h"
@@ -62,6 +61,14 @@ ThreatCostTable computeThreatCostTable(const GameConfig& config)
 {
     ThreatCostTable table;
 
+    // Scrap threat (REQ-THREAT-SCRAP) is the constant inverse of the scrap-drop
+    // conversion (REQ-RES-SCRAP-DROP): one scrap is worth 1 / scrap_per_threat.
+    // Set it up front so reprocessing-only item threats (below) can use it, and so
+    // it no longer depends on any ship's threat cost.
+    table.scrapThreat = config.world.scrapPerThreat > 0.0
+        ? 1.0 / config.world.scrapPerThreat
+        : 0.0;
+
     // Build lookup: output item → non-reprocessing recipes and reprocessing recipes.
     std::map<std::string, std::vector<RecipeRef>> nonReprocessingRecipes;
     std::map<std::string, std::vector<RecipeRef>> reprocessingRecipes;
@@ -146,26 +153,6 @@ ThreatCostTable computeThreatCostTable(const GameConfig& config)
         }
     }
 
-    // Compute scrap threat (REQ-THREAT-SCRAP): find the ship with the smallest
-    // scrap_drop and use its threat cost.
-    int minScrapDrop = std::numeric_limits<int>::max();
-    const ShipDef* cheapestScrapShip = nullptr;
-    for (const ShipDef& def : config.ships.ships)
-    {
-        if (def.loot.scrapDrop > 0 && def.loot.scrapDrop < minScrapDrop)
-        {
-            minScrapDrop = def.loot.scrapDrop;
-            cheapestScrapShip = &def;
-        }
-    }
-
-    if (cheapestScrapShip != nullptr)
-    {
-        double shipThreat = calculateShipThreatCost(table, config,
-            cheapestScrapShip->id, cheapestScrapShip->defaultModules);
-        table.scrapThreat = shipThreat / minScrapDrop;
-    }
-
     // Resolve reprocessing-only items.
     for (const std::string& item : unresolved)
     {