Stage 4: Web3 black market spot counter and Ponero desk

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

src/Decentralized/Unlock.cs

@@ -15,6 +15,9 @@ namespace Decentralized
         public const int MixerPrice = Domain.Tuning.MixerUnlockPrice;
         public static bool MixerUnlocked => PlayerStore.Instance != null && ModHelper.IsNetworkUpgradeUnlocked(MixerId);
 
+        public const string BlackId = "PD_BLACKMARKET";
+        public static bool BlackUnlocked => PlayerStore.Instance != null && ModHelper.IsNetworkUpgradeUnlocked(BlackId);
+
         public static bool IsUnlocked => PlayerStore.Instance != null && ModHelper.IsNetworkUpgradeUnlocked(Id);
 
         public static void Register()
@@ -26,6 +29,7 @@ namespace Decentralized
             // 每个升级单独 try，免得前一个抛异常时后面的没登记上。
             Add(Id, Price, () => L.T("upgrade.title"), () => L.T("upgrade.desc"), OnPurchased, "terminal", null);
             Add(MixerId, MixerPrice, () => L.T("mixer.upgrade.title"), () => L.T("mixer.upgrade.desc"), () => Log.Info("混币器已解锁"), "ui_web3", new[] { Id });
+            Add(BlackId, Domain.Tuning.BmUnlockPrice, () => L.T("black.upgrade.title"), () => L.T("black.upgrade.desc"), () => Log.Info("Web3 黑市已解锁"), "ui_web3", new[] { Id });
         }
 
         private static void Add(string id, int price, Func<string> title, Func<string> desc, Action onUnlock, string icon, string[] prerequisites)