Used-hardware dealer customer and GPU appraisal registration

A scav-type seller visits now and then with three to five used cards. An
honest dealer sells at true value, a middleman adds 8%, a scammer mixes in
fakes (relabelled cheap chips) priced at 90% of the labelled model's value.
The markup is a client-temporary item feature, so a bought card is only
worth its real value. Cards are registered as appraisal items; the correct
value is the same function as the sale value.

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

src/Decentralized/UsedDealerClient.cs

@@ -0,0 +1,99 @@
+using System.Collections.Generic;
+using Decentralized.Domain;
+
+namespace Decentralized
+{
+    /// <summary>
+    /// 二手显卡贩子：偶尔上门，把几张卡摆上柜台，玩家按外观自己判断（翻面看背面）。
+    /// 老实人按真实价值卖，中间商加价，骗子夹带假卡并按标称型号报价；价格是柜台上的临时加价，买下之后卡只值真实价值。
+    /// 另外把显卡登记为鉴定公会的鉴定物品，正确价值与实际售价是同一个数。
+    /// </summary>
+    public static class UsedDealerClient
+    {
+        public const string Appraisal = "pd_gpu_appraisal";
+        private const double VisitChance = 0.05;
+        private static int lastVisitDay = -1;
+
+        public static void Subscribe()
+        {
+            ModHook.OnGenerateCustomerNormal += OnGenerate;
+            ModHelper.AddAppraisalItem(ModInfo.Id, Appraisal, Items.GpuId("RZX50"), 2, CreateForAppraisal, u => (int)CardValue.True(Items.ToUnit(u)),
+                Items.IsGpu, null, () => L.T("appraisal.gpu"));
+            ModHelper.AddDebugFunction(ModInfo.Id, ModInfo.Name, "Used dealer visit (test)", () => PlayerStore.Instance.storeClientManager?.AddClient(Create(DealerKind.Scammer)));
+        }
+
+        public static void Unsubscribe()
+        {
+            ModHook.OnGenerateCustomerNormal -= OnGenerate;
+            ModHelper.RemoveAppraisalItems(ModInfo.Id);
+        }
+
+        private static void OnGenerate(StoreClientManager manager)
+        {
+            if (Session.Data == null || !Unlock.IsUnlocked) return;
+            Log.Guard("二手贩子", () =>
+            {
+                int day = StoreStation.GetDayCounter();
+                if (day < 3 || day == lastVisitDay || !Session.Data.Rng.Chance(VisitChance)) return;
+                lastVisitDay = day;
+                manager.AddClient(Create(UsedDealers.Kind(day, Session.Data.Rng)));
+            });
+        }
+
+        /// <summary>鉴定公会送来的卡：一成是假卡；默认估价是按标称型号算的价。</summary>
+        private static GameItem CreateForAppraisal()
+        {
+            var rng = Session.Data?.Rng ?? new Rng(1);
+            int day = StoreStation.GetDayCounter();
+            var cards = UsedDealers.Cards(DealerKind.Middleman, day, rng);
+            var c = cards[0];
+            var item = Items.NewCard(c.Model, c.Health, c.FakeOf, rng);
+            AppraisalHelper.InitAppraisalItem(item, (int)CardValue.Of(c.Model, c.Health));
+            return item;
+        }
+
+        private static StoreClient Create(DealerKind kind)
+        {
+            int day = StoreStation.GetDayCounter();
+            var rng = Session.Data.Rng;
+            var cards = UsedDealers.Cards(kind, day, rng);
+            var client = new StoreClient
+            {
+                identifier = "pd_used_dealer",
+                displayName = L.T("dealer.name"),
+                spriteName = SpriteDict.GetRandomScavSpriteName(),
+                clientIntent = StoreClient.ClientIntent.SELL,
+            };
+            StoreClientFactionSetup.InitScav(client);
+            client.mainDialogue.SetText(client.displayName, L.T("dealer.line1." + rng.Range(1, 3))).NextDialogue().SetText(client.displayName, L.T("dealer.line2." + rng.Range(1, 3)))
+                .SetEndAction(() => Log.Guard("二手贩子上货", () =>
+                {
+                    NegociationUIManager.Instance.OpenUI();
+                    var placed = new List<string>();
+                    foreach (var c in cards)
+                    {
+                        var item = Items.NewCard(c.Model, c.Health, c.FakeOf, rng);
+                        if (c.MarkupPct != 0) item.AddItemFeature(Markup(c.MarkupPct));
+                        PlayerStore.Instance.AddDirectSellingItemToTable(item);
+                        placed.Add($"{c.Model}{(c.FakeOf != null ? "←" + c.FakeOf : "")} {c.Health:0}% {c.MarkupPct:+0;-0}%");
+                    }
+                    Log.Info($"二手贩子（{kind}）：{string.Join("，", placed)}");
+                }));
+            client.AddBasicDialog();
+            client.CompleteClientCreation();
+            return client;
+        }
+
+        /// <summary>柜台上的临时加价：离开贩子之后自动去掉（游戏按客户临时特征处理）。</summary>
+        private static ItemFeature Markup(int pct)
+        {
+            var f = new ItemFeature(ItemFeature.FeatureType.ClientTemporary) { identifier = "pd_used_markup", category = "markup", valueStage = ItemFeature.ValueStage.Market };
+            string text = L.T("dealer.markup");
+            f.SetPublicDisplay(text);
+            f.SetActualDisplay(text);
+            f.isFeatureMatch = true;
+            f.SetPreExposedValueMod(pct);
+            return f;
+        }
+    }
+}