终端只重建内容区并合并同帧刷新；平台费页文案；按住签名随 Gas 档位缩短

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

src/Decentralized.Domain/TuningTable.cs

@@ -399,6 +399,7 @@ namespace Decentralized.Domain
             ["TxGasNoise"] = Tuning.TxGasNoise,
             ["TxGasPeriod"] = Tuning.TxGasPeriod,
             ["TxHijackChance"] = Tuning.TxHijackChance,
+            ["TxHoldSecs"] = Tuning.TxHoldSecs,
             ["TxPhishChance"] = Tuning.TxPhishChance,
             ["TxPoisonChance"] = Tuning.TxPoisonChance,
             ["TxPoisonDelayMax"] = Tuning.TxPoisonDelayMax,