R8: Accounting- + Supervisor-Modul + Core-Datenfundament (S-0)

Portierung der beiden fehlenden Grundbausteine aus PolytraderSharp (voller Ausbau).

Core S-0 (Datenfundament fuer Analyse/Forensik):
- core_decision_journal + core_order_events (+ ReasonCode/Decision/OrderEvent-Enums),
  IDecisionJournal/IOrderEventLog mit fehlertoleranten EF-Impls (Handel bricht nie).
- SignalId-Durchreichung TradeSignal -> ExecutionService -> core_trade_history;
  ExecutionService schreibt an jeder Verzweigung Journal/Order-Events.
- JSONL-Log-Sink (LogJson + Dual-Sink), pure Analytik: RealizedPnlEngine (FIFO),
  TradeAnalytics, DossierBuilder. Migration AddAnalysisFoundation.

Accounting-Modul (acc_): unabhaengiger IBKR-Kontoauszug (Activity Flex Query) hinter
Interfaces mit Offline-Null-Stubs -> append-only Ledger + Periodenabrechnung/BWA + FX
(USD/EUR) + CSV/PDF (PDFsharp/MigraDoc). Steuerschicht bewusst offen (Platzhalter-Tab).
Kein Handel. Migration InitialAccounting.

Supervisor-Modul (sup_): read-only OpenRouter-Agent (Function-Calling-Loop) + read-only
Tool-Registry (8 Tools) + Profile + Dossier-Browser + Counterfactual-Job (Stub) +
Tagesbericht/MCP-Light (opt-in). Migration InitialSupervisor.

Verdrahtung: Program.cs (beide Module + Icons), slnx/App/Tests-Referenzen,
provision-db.ps1, AppSettings-Sektionen, docs/konzepte, README.

Tests: 79 -> 117 gruen (FIFO/KPIs/Dossier/JSONL, Classifier/Engine/FX/Idempotenz,
OpenRouter/Registry/Agent/MCP, STA-Konstruktion beider neuen Fenster).

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

tests/IBKRTrader.Tests/Logging/LogJsonTests.cs

@@ -0,0 +1,43 @@
+using FluentAssertions;
+using IBKRTrader.Core.Logging;
+
+namespace IBKRTrader.Tests.Logging;
+
+[Trait("cat", "unit")]
+public class LogJsonTests
+{
+    [Fact]
+    public void RoundTrip_PreservesFields()
+    {
+        var ts = new DateTime(2026, 7, 30, 12, 34, 56, DateTimeKind.Utc);
+        var line = LogJson.WriteLine(ts, AppLogLevel.Warn, "CT", "Kurs fehlt für AAPL", "sig-123");
+
+        var parsed = LogJson.ParseLine(line);
+
+        parsed.Should().NotBeNull();
+        parsed!.Ts.Should().Be(ts);
+        parsed.Level.Should().Be("Warn");
+        parsed.Source.Should().Be("CT");
+        parsed.Cid.Should().Be("sig-123");
+        parsed.Message.Should().Be("Kurs fehlt für AAPL");
+    }
+
+    [Fact]
+    public void WriteLine_OmitsCid_WhenNull()
+    {
+        var line = LogJson.WriteLine(DateTime.UtcNow, AppLogLevel.Info, "Core", "hello", null);
+
+        line.Should().NotContain("cid");
+        LogJson.ParseLine(line)!.Cid.Should().BeNull();
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("   ")]
+    [InlineData("nicht json")]
+    [InlineData("{ kaputt")]
+    public void ParseLine_ReturnsNull_OnGarbage(string input)
+    {
+        LogJson.ParseLine(input).Should().BeNull();
+    }
+}