Phase 2: CRT freeze during crackdowns (frozen balance, thaw, news, test entry)

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

src/Decentralized.Domain/Mixer.cs

@@ -47,7 +47,7 @@ namespace Decentralized.Domain
         /// <summary>存入：从钱包按价值比例带走污点与成本。轮数超出范围或余额不足返回 null。</summary>
         public MixDeposit Deposit(Wallet w, string asset, double amount, int rounds, int day, Func<string, double> price)
         {
-            if (rounds < 1 || rounds > Tuning.MixerMaxRounds || amount <= 0 || w.Get(asset) + 1e-9 < amount) return null;
+            if (rounds < 1 || rounds > Tuning.MixerMaxRounds || amount <= 0 || w.Avail(asset) + 1e-9 < amount) return null;
             double value = amount * price(asset);
             if (value < Tuning.MixerMin) return null;
             double total = w.Value(price);