Phase 2: mixer (Web3 tab in the network, terminal page, sanctions, night return), unlock registration per upgrade

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

src/Decentralized/Session.cs

@@ -25,6 +25,7 @@ namespace Decentralized
         public Network Network = new Network();
         public Wallet Hot = new Wallet { Address = "hot" };
         public Exchange Exchange = new Exchange();
+        public Mixer Mixer = new Mixer();
         public List<MarketEvent> ActiveEvents = new List<MarketEvent>();
         public NightReport LastNight;
         public bool OpeningNewsShown;