Coin payment premium 12%

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/Decentralized.Domain/CoinPayment.cs

@@ -33,11 +33,11 @@ namespace Decentralized.Domain
             }
         }
 
-        /// <summary>收款：返回收到的币数。heatPct 是物品的赃物热度（0–100）。</summary>
+        /// <summary>收款：返回收到的币数。heatPct 是物品的赃物热度（0–100）。多付的溢价是顾客给的额外收入，不带污点。</summary>
         public static double Receive(Wallet w, string asset, double credits, double price, double heatPct)
         {
             if (credits <= 0 || price <= 0) return 0;
-            double qty = credits / price;
+            double qty = credits * (1 + Tuning.CoinPayPremium) / price;   // 溢价只加在币数上，污点与成本仍按货值算
             w.Add(asset, qty);
             w.Taint += credits * Math.Max(0, Math.Min(100, heatPct)) / 100.0;
             w.Basis += credits;

src/Decentralized.Domain/Tuning.cs

@@ -65,6 +65,8 @@ namespace Decentralized.Domain
         public const int MixerMaxRounds = 5, MixerSanctionDays = 5;
         /// <summary>各派系顾客用币付款的概率。</summary>
         public const double CoinPayCrc = 0.30, CoinPayCrt = 0.50, CoinPayCra = 0.50, CoinPayPsc = 0.25;
+        /// <summary>用币付款的溢价：顾客多付的比例，补偿持币的污点与兑出的手续费。</summary>
+        public const double CoinPayPremium = 0.12;
         /// <summary>单个金融违规事件记入的罪证上限。</summary>
         public const double CrimeEventCap = 400;