Domain: market, stablecoins, compliant cash-out with AML

Market: PSCoin reference price with sentiment, anchor shifts from game
events (blackout, crackdown), daily volatility, NPC whales, a day-average
mark price, and side pairs pulled toward the reference by arbitrage.
Stablecoins: CRC depeg and haircut, CRT depeg and freeze chance by black
market reputation, CRA staking subsidy, warnings and the three-day spiral.
Exchange: CRC cash-out at market price, AML hit chance from size, 7-day
total, taint ratio and mixer/flag; light hits confiscate the tainted part,
heavy hits also report it as fencing; tax only on gains.

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

src/Decentralized.Domain/Exchange.cs

@@ -0,0 +1,76 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace Decentralized.Domain
+{
+    public enum AmlOutcome { Clear, Light, Heavy }
+
+    /// <summary>一次合规出金的结果。罪证由接入层记进游戏的罪证账本（销赃）。</summary>
+    public sealed class CashoutResult
+    {
+        public double Requested;
+        public double Received;
+        public double Confiscated;
+        public double Crime;
+        public double Tax;
+        public double HitChance;
+        public AmlOutcome Outcome;
+    }
+
+    /// <summary>
+    /// 合规交易所出金：CRC 兑回信用点，过 AML。审查按单笔金额、7 天累计金额、污点比例、是否来自混币器或被标记地址判定。
+    /// 轻度命中（污点 &lt; 30%）没收污点部分、不记罪证；重度命中没收污点部分，并把污点额记为销赃罪证。
+    /// </summary>
+    public sealed class Exchange
+    {
+        /// <summary>最近的出金记录：(天, 金额)。</summary>
+        public List<KeyValuePair<int, double>> History = new List<KeyValuePair<int, double>>();
+
+        public static double HitChance(double amount, double taint, double recentTotal, double rent, bool fromMixerOrFlagged)
+        {
+            if (amount <= 0) return 0;
+            double ratio = taint / amount;
+            double big = Tuning.AmlBigRents * rent, cum = Tuning.AmlCumRents * rent;
+            double p = 0;
+            if (ratio >= Tuning.AmlTaintRatio) p += ratio * 1.5;
+            p += Math.Max(0, (amount - big) / big) * 0.2;
+            p += Math.Max(0, (recentTotal + amount - cum) / cum) * 0.2;
+            if (fromMixerOrFlagged) p += Tuning.AmlMixerBonus;
+            return Math.Min(Tuning.AmlMaxChance, p);
+        }
+
+        /// <summary>
+        /// 从地址里取出 amount 个 CRC 兑成信用点（按 CRC 当前价格，平时为 1；脱锚期间按市价），扣手续费。污点与成本按比例随取出部分计算；
+        /// 只对超出成本的部分计税。
+        /// </summary>
+        public CashoutResult Cashout(Wallet wallet, double amount, Func<string, double> price, int day, double rent, bool fromMixer, Rng rng)
+        {
+            amount = Math.Min(amount, wallet.Get(Assets.CRC));
+            var r = new CashoutResult { Requested = amount };
+            if (amount <= 0) return r;
+            double total = wallet.Value(price);
+            double share = total > 0 ? Math.Min(1, amount * price(Assets.CRC) / total) : 0;
+            double taint = wallet.Taint * share, basis = wallet.Basis * share;
+            History.RemoveAll(h => h.Key <= day - Tuning.AmlWindowDays);
+            double recent = History.Sum(h => h.Value);
+            double value = amount * price(Assets.CRC);
+            r.HitChance = HitChance(value, taint, recent, rent, fromMixer || wallet.Flagged);
+            wallet.Add(Assets.CRC, -amount);
+            wallet.Taint -= taint;
+            wallet.Basis -= basis;
+            History.Add(new KeyValuePair<int, double>(day, value));
+            double got = value * (1 - Tuning.ExchangeFee);
+            if (rng.Chance(r.HitChance))
+            {
+                r.Outcome = taint / value >= Tuning.AmlHeavyRatio ? AmlOutcome.Heavy : AmlOutcome.Light;
+                r.Confiscated = Math.Min(got, taint);
+                got -= r.Confiscated;
+                if (r.Outcome == AmlOutcome.Heavy) r.Crime = taint;
+            }
+            r.Tax = Math.Max(0, got - basis) * Tuning.TaxRate;
+            r.Received = got;
+            return r;
+        }
+    }
+}