ui: black market buy page with seller list, payment panel, per-merchant accepted coins and auto-convert; wallet row keys beside the data cells

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

src/Decentralized.Domain/Tuning.cs

@@ -237,6 +237,9 @@ namespace Decentralized.Domain
         public const double FakeSupportChance = 0.04, FakeTransferShare = 0.08;
         public const int ScamMinDay = 10;
 
+        /// <summary>Web3 内置自动换币：商家不收手里的币时，按这个比例多付（DEX 手续费 0.3% 加上高滑点），省得自己去换。</summary>
+        public const double BmAutoSwapSlip = 0.08;
+
         /// <summary>剧情联动：塞尔皮科证据交给革命军（CRA 补贴池注资、螺旋概率倍率与期限、SPARK 几晚内涨到的倍数）、交给黑市（CRT 脱锚与被出卖的倍率）、
         /// 交给治安部（期限内出金审查命中、混币器制裁、操纵与内幕查处的倍率）；埃莉诺泄露数据盘（CRC 托管减记倍率、SPARK 涨幅）、交回（CRC 脱锚倍率）；
         /// 伦警官被捕（期限与查处倍率）；SPARK 推涨分几晚走完。</summary>