Stage 6.2: Poinbase perpetual futures (PSC, SPARK) with slippage, funding, insurance fund, ADL, debt and seizure

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

src/Decentralized/Session.cs

@@ -31,6 +31,8 @@ namespace Decentralized
         public Stablecoins Stable = new Stablecoins();
         /// <summary>革命军 CRA 质押池里玩家各钱包的仓位。</summary>
         public Staking Staking = new Staking();
+        /// <summary>Poinbase 永续合约账本（保证金用 Poinbase 账户的 CRC）。</summary>
+        public PerpBook Perps = new PerpBook();
         /// <summary>质押日息下调的新闻已经发过。</summary>
         public bool CraLowNews;
         public Network Network = new Network();