Prediction markets use on-chain wallets (signed contract calls) instead of the Poinbase account

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

src/Decentralized/Night.cs

@@ -184,7 +184,7 @@ namespace Decentralized
             if (d.Network.Reward < rewardBefore) News.Show("pd_news_halving_" + day, L.T("news.halving.title"), L.T("news.halving.desc"), 2);
             // 预测市场：先登记今晚的观测再结算到期的盘口；行情盘读夜间更新之前的价格
             var predictEvents = PredictGame.Available(day) || d.Predict.Markets.Count > 0
-                ? d.Predict.Night(day, PredictGame.ActiveIds(), m => PredictGame.Outcome(m, d), d.Poinbase, d.Rng) : new List<PredictEvent>();
+                ? d.Predict.Night(day, PredictGame.ActiveIds(), m => PredictGame.Outcome(m, d), d.WalletAt, d.Rng) : new List<PredictEvent>();
             // 永续：用今天的标记价（当日均价）结算，要在今晚的价格更新之前
             var perpEvents = d.Perps.Night(day, new Dictionary<string, double> { ["PSC"] = d.Market.Mark, ["SPARK"] = d.Stable.Spark }, d.Poinbase, Session.Price);
             if (perpEvents.Any(e => e.Kind == "seize")) SeizeForDebt(d, day);