Slice 0 (Fable-Fixes): IClobClient-Seam fuer testbare CLOB-Interaktionen

Verhaltensneutrale Testinfrastruktur als Grundlage fuer Slice 1/2:
- IClobClient-Interface (Core) ueber die von Leiter/Reconciliation genutzten
  CLOB-Methoden (Place/CancelConflicting/GetOpenOrders/CancelOrder).
- PolymarketClobClient implementiert IClobClient (Signaturen unveraendert).
- DI-Seam im Modul: IClobClient -> PolymarketClobClient-Singleton.
- SellLadderService haengt jetzt an IClobClient (statische CalculateExactOrderAmounts
  bleibt am konkreten Typ).
- InternalsVisibleTo(PolyTrader.Tests) + FakeClobClient-Test-Double.

Verifikation: Build 0 Fehler, 207 Tests gruen, --smoke-ui Container-Aufbau ok.

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

src/PolyTrader.Modules.CopyTrading/CopyTradingModule.cs

@@ -66,6 +66,10 @@ namespace PolyTrader.Modules.CopyTrading
             services.AddHostedService<AlchemyWebsocketService>();
             services.AddHostedService<PolymarketWssClient>();
 
+            // IClobClient-Seam: Leiter/Reconciliation hängen am Interface (mockbar für Integrationstests);
+            // die Live-Instanz ist der eine PolymarketClobClient-Singleton aus dem App-Container.
+            services.AddSingleton<IClobClient>(sp => sp.GetRequiredService<PolymarketClobClient>());
+
             // Phase 0.1: SELL-Eskalationsleiter (preist offene Exit-Limits stufenweise nach).
             // Singleton + Hosted, damit Engine und TraderMonitor StartLadderAsync aufrufen können.
             services.AddSingleton<SellLadderService>();

src/PolyTrader.Modules.CopyTrading/PolyTrader.Modules.CopyTrading.csproj

@@ -4,6 +4,13 @@
     <ProjectReference Include="..\PolyTrader.Core\PolyTrader.Core.csproj" />
   </ItemGroup>
 
+  <!-- Erlaubt dem Testprojekt, interne Service-Methoden (z.B. Leiter-Tick) integrationszutesten. -->
+  <ItemGroup>
+    <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleToAttribute">
+      <_Parameter1>PolyTrader.Tests</_Parameter1>
+    </AssemblyAttribute>
+  </ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="Pomelo.EntityFrameworkCore.MySql" Version="8.0.3" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="8.0.11">

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

@@ -27,7 +27,7 @@ namespace PolyTraderSharp.Services
 
         private readonly CopyTradingState _copyState;
         private readonly TradingState _state;
-        private readonly PolymarketClobClient _clob;
+        private readonly IClobClient _clob;
         private readonly TerminalLogger _logger;
         private readonly ThreemaService _threema;
         private readonly IPositionRepository _positionRepo;
@@ -35,7 +35,7 @@ namespace PolyTraderSharp.Services
         public SellLadderService(
             CopyTradingState copyState,
             TradingState state,
-            PolymarketClobClient clob,
+            IClobClient clob,
             TerminalLogger logger,
             ThreemaService threema,
             IPositionRepository positionRepo)