Fold scattered constants into Tuning

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

src/Decentralized/UsedDealerClient.cs

@@ -12,8 +12,7 @@ namespace Decentralized
     public static class UsedDealerClient
     {
         public const string Appraisal = "pd_gpu_appraisal";
-        private const double VisitChance = 0.05;
-        private static int lastVisitDay = -1;
+                private static int lastVisitDay = -1;
 
         public static void Subscribe()
         {
@@ -55,7 +54,7 @@ namespace Decentralized
             Log.Guard("二手贩子", () =>
             {
                 int day = StoreStation.GetDayCounter();
-                if (day < 3 || day == lastVisitDay || !Session.Data.Rng.Chance(VisitChance)) return;
+                if (day < Tuning.UsedFirstDay || day == lastVisitDay || !Session.Data.Rng.Chance(Tuning.UsedVisitChance)) return;
                 lastVisitDay = day;
                 manager.AddClient(Create(UsedDealers.Kind(day, Session.Data.Rng)));
             });