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/Modules/Accounting/AccountingEngineTests.cs

@@ -0,0 +1,75 @@
+using FluentAssertions;
+using IBKRTrader.Modules.Accounting.Logic;
+using IBKRTrader.Modules.Accounting.Models;
+
+namespace IBKRTrader.Tests.Modules.Accounting;
+
+[Trait("cat", "unit")]
+public class AccountingEngineTests
+{
+    private static LedgerEntry E(LedgerEventType type, decimal net, decimal gross, int day, decimal fee = 0m) =>
+        new()
+        {
+            AccountId = "U1", EventType = type, NetBase = net, GrossBase = gross, FeeBase = fee,
+            Timestamp = new DateTime(2026, 3, day, 12, 0, 0, DateTimeKind.Utc)
+        };
+
+    [Fact]
+    public void Statement_SatisfiesBalanceInvariant()
+    {
+        var entries = new[]
+        {
+            E(LedgerEventType.Deposit, 1000m, 1000m, 1),
+            E(LedgerEventType.TradeBuy, -500m, 499m, 2, fee: 1m),
+            E(LedgerEventType.TradeSell, 650m, 651m, 3, fee: 1m),
+            E(LedgerEventType.Dividend, 20m, 20m, 4),
+            E(LedgerEventType.Withdrawal, -200m, 200m, 5)
+        };
+
+        var s = AccountingEngine.BuildStatement(entries, new DateTime(2026, 3, 1, 0, 0, 0, DateTimeKind.Utc),
+            new DateTime(2026, 3, 31, 23, 59, 59, DateTimeKind.Utc), "U1");
+
+        // Invariante: Endsaldo − Anfang = Ergebnis + Einzahlungen − Auszahlungen
+        s.BalanceChange.Should().Be(s.NetTradingResult + s.Deposits - s.Withdrawals);
+        s.Deposits.Should().Be(1000m);
+        s.Withdrawals.Should().Be(200m);
+        s.Dividends.Should().Be(20m);
+        s.Fees.Should().Be(2m);
+        s.TradeCount.Should().Be(2);
+        s.ClosingBalance.Should().Be(970m);   // 1000 -500 +650 +20 -200
+    }
+
+    [Fact]
+    public void OpeningBalance_AccumulatesEntriesBeforeFrom()
+    {
+        var entries = new[]
+        {
+            E(LedgerEventType.Deposit, 500m, 500m, 1),     // vor dem Zeitraum
+            E(LedgerEventType.Dividend, 30m, 30m, 20)      // im Zeitraum
+        };
+
+        var s = AccountingEngine.BuildStatement(entries, new DateTime(2026, 3, 10, 0, 0, 0, DateTimeKind.Utc),
+            new DateTime(2026, 3, 31, 0, 0, 0, DateTimeKind.Utc), "U1");
+
+        s.OpeningBalance.Should().Be(500m);
+        s.ClosingBalance.Should().Be(530m);
+    }
+
+    [Fact]
+    public void MonthlyBreakdown_ChainsOpeningBalances()
+    {
+        var entries = new[]
+        {
+            E(LedgerEventType.Deposit, 100m, 100m, 1),   // März
+            E(LedgerEventType.Dividend, 10m, 10m, 5)
+        };
+
+        var monthly = AccountingEngine.BuildMonthlyBreakdown(entries,
+            new DateTime(2026, 3, 1, 0, 0, 0, DateTimeKind.Utc),
+            new DateTime(2026, 4, 30, 0, 0, 0, DateTimeKind.Utc), "U1");
+
+        monthly.Should().HaveCount(2);
+        monthly[0].From.Month.Should().Be(3);
+        monthly[1].OpeningBalance.Should().Be(monthly[0].ClosingBalance);  // April startet mit März-Endsaldo
+    }
+}