Stage 6.1: CRA staking pool, SPARK balance token with mint/burn

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

src/Decentralized.Domain/Stablecoins.cs

@@ -15,6 +15,8 @@ namespace Decentralized.Domain
         public double CraSubsidy = Tuning.CraSubsidy0;
         public int CraWarnDay = -1, CraSpiralDay = -1;
         public double RevPower = 50;
+        /// <summary>平衡代币 SPARK 的价格（信用点）；SparkPre 是螺旋开始前一刻的价格，螺旋三天按它的倍数走。</summary>
+        public double Spark = Tuning.SparkStart, SparkPre = -1;
         public List<double> RevHistory = new List<double>();
 
         public double Price(string asset)
@@ -24,6 +26,7 @@ namespace Decentralized.Domain
                 case Assets.CRC: return Crc;
                 case Assets.CRT: return Crt;
                 case Assets.CRA: return Cra;
+                case Assets.SPARK: return Spark;
                 default: return 1;
             }
         }
@@ -42,6 +45,8 @@ namespace Decentralized.Domain
                 Crt = rng.Range(Tuning.CrtDepegMin, Tuning.CrtDepegMax);
                 CrtDepegEnd = day + rng.Range(Tuning.CrtDepegDaysMin, Tuning.CrtDepegDaysMax);
             }
+            if (ev == MarketEvent.RevRaidUpper) Spark *= Tuning.SparkRaidShock;
+            if (ev == MarketEvent.LowerUnrest) Spark *= Tuning.SparkUnrestShock;
             return 1;
         }
 
@@ -52,6 +57,26 @@ namespace Decentralized.Domain
         /// <summary>镇压开始时是否冻结玩家的 CRT：按黑市声望，声望越低越容易被黑市"出卖"。</summary>
         public static bool CrtFrozenByCrackdown(double blackMarketRep, Rng rng) => rng.Chance(CrtFreezeChance(blackMarketRep));
 
+        /// <summary>铸造：用 CRA 按当前价换 SPARK，收手续费。余额不足返回 -1。</summary>
+        public double Mint(Wallet w, double cra)
+        {
+            if (cra <= 0 || Spark <= 0 || w.Avail(Assets.CRA) + 1e-9 < cra) return -1;
+            double got = cra * Cra / Spark * (1 - Tuning.SparkFee);
+            w.Add(Assets.CRA, -cra); w.Add(Assets.SPARK, got);
+            w.RecordBuy(Assets.SPARK, got, cra * Cra);
+            return got;
+        }
+
+        /// <summary>销毁：用 SPARK 按当前价换 CRA，收手续费。余额不足返回 -1。</summary>
+        public double Burn(Wallet w, double spark)
+        {
+            if (spark <= 0 || Cra <= 0 || w.Avail(Assets.SPARK) + 1e-9 < spark) return -1;
+            double got = spark * Spark / Cra * (1 - Tuning.SparkFee);
+            w.Add(Assets.SPARK, -spark); w.Add(Assets.CRA, got);
+            w.RecordBuy(Assets.CRA, got, spark * Spark);
+            return got;
+        }
+
         public bool CraSubsidyLow => CraSubsidy <= Tuning.CraSubsidy0 * Tuning.CraSubsidyWarn;
 
         /// <summary>CRA 的预兆：外生螺旋的新闻已出，或补贴池告急（利率下调）。螺旋开始后不再算预兆。</summary>
@@ -95,7 +120,18 @@ namespace Decentralized.Domain
                 }
             }
             if (CraSpiralDay > 0 && day >= CraSpiralDay)
-                Cra = Tuning.CraSpiralPath[Math.Min(day - CraSpiralDay, Tuning.CraSpiralPath.Length - 1)];
+            {
+                int k = Math.Min(day - CraSpiralDay, Tuning.CraSpiralPath.Length - 1);
+                Cra = Tuning.CraSpiralPath[k];
+                if (SparkPre < 0) SparkPre = Spark;
+                Spark = SparkPre * Tuning.SparkSpiralPath[Math.Min(day - CraSpiralDay, Tuning.SparkSpiralPath.Length - 1)];
+            }
+            else
+            {
+                Spark *= Math.Exp(rng.Gauss() * Tuning.SparkVol);
+                Spark += (Tuning.SparkStart - Spark) * Tuning.SparkRevert;
+                Spark = Math.Max(Tuning.SparkStart * Tuning.SparkMinMult, Math.Min(Tuning.SparkStart * Tuning.SparkMaxMult, Spark));
+            }
             return crcFactor;
         }
     }