K1a-Testabdeckung: Cleanup schont aktive Leiter (Floor-Deadlock)

Verifiziert den kritischen K1a-Fix mit Integrationstests statt nur per Review
(nach dem K3-Fehlplatzierungs-Fund):
- TraderMonitorService._clob -> IClobClient (verhaltensneutral); CleanupStaleOpenOrdersAsync
  internal. FakeCopyTradeLogRepository ergaenzt.
- 2 Tests: Stale Order mit aktiver Leiter wird NICHT gecancelt; ohne Leiter WIRD sie
  storniert (Kontrast, beweist Nicht-Vacuositaet).

Build 0 Fehler, 244 Tests gruen, --smoke-ui ok.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/PolyTrader.Modules.CopyTrading/Services/TraderMonitorService.cs

@@ -18,7 +18,7 @@ namespace PolyTraderSharp.Services
         private readonly TradingState _state;
         private readonly CopyTradingState _copyState;
         private readonly PolymarketApiService _api;
-        private readonly PolymarketClobClient _clob;
+        private readonly IClobClient _clob;
         private readonly ChannelWriter<CopySignal> _signalWriter;
         private readonly ChannelWriter<ClosedTrade> _closedTradeWriter;
         private readonly TerminalLogger _logger;
@@ -47,7 +47,7 @@ namespace PolyTraderSharp.Services
             TradingState state,
             CopyTradingState copyState,
             PolymarketApiService api,
-            PolymarketClobClient clob,
+            IClobClient clob,
             ChannelWriter<CopySignal> signalWriter, 
             ChannelWriter<ClosedTrade> closedTradeWriter,
             TerminalLogger logger,
@@ -1148,7 +1148,7 @@ namespace PolyTraderSharp.Services
             }
         }
 
-        private async Task CleanupStaleOpenOrdersAsync(CancellationToken ct)
+        internal async Task CleanupStaleOpenOrdersAsync(CancellationToken ct)
         {
             var keysToProcess = _copyState.PendingOrderTimestamps.ToArray();
             if (keysToProcess.Length == 0) return;