Phase 7: Tests erweitert + Mongo-Parser extrahiert (testbar)

Tests (jetzt 48 grün):
- DbContextMappingTests: sichert core_/mod_-Tabellennamen, Position-Composite-Key,
  TrackedTrader-Key, ClosedTradeRow nicht gemappt, AccountState.OpenPositions ignoriert.
- PositionRepositoryTests: Live/Demo-Trennung, Upsert setzt Account+Demo-Flag,
  Update ohne Duplikat, DeleteLive, DropDemo.
- MarketRepositoryTests: GetActive filtert Closed, Upsert-Update, FindByTokenId.
- TradeLogRepositoryTests: GetRecent (Sortierung+Limit), Find-Predikat, Guid-Id unique.
- MongoExportParserTests: String-Dezimale, null->"", fehlende Felder->Default,
  AssignedAccountIds-Array, Category-Default, Nicht-Array->leer.

Refactor:
- Mongo-Export-Parsing aus ConfigMigrator in testbare Klasse
  PolyTrader.Modules.CopyTrading.ConfigImport.MongoExportParser ausgelagert
  (ParseAccounts -> Account+Settings, ParseTraders). ConfigMigrator nutzt sie;
  --migrate-json end-to-end verifiziert (3/3/32).
- PolyTrader.App.csproj: tests/** vom Default-Glob ausgeschlossen (App zog sonst
  die Testdateien mit rein -> doppelte AssemblyInfo/Xunit-Fehler).

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

tests/PolyTrader.Tests/TradeLogRepositoryTests.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Linq;
+using PolyTrader.Core.Persistence.Ef;
+using PolyTrader.Tests.TestSupport;
+using PolyTraderSharp.Models;
+using Xunit;
+
+namespace PolyTrader.Tests
+{
+    public class TradeLogRepositoryTests
+    {
+        private static EfTradeLogRepository NewRepo() =>
+            new(new InMemoryContextFactory<CoreDbContext>(o => new CoreDbContext(o)));
+
+        [Fact]
+        public void GetRecent_orders_by_closed_at_descending_and_limits()
+        {
+            var repo = NewRepo();
+            var t = new DateTime(2026, 7, 1, 0, 0, 0, DateTimeKind.Utc);
+            repo.Insert(new TradeRecord { Id = "a", ClosedAt = t.AddHours(1) });
+            repo.Insert(new TradeRecord { Id = "b", ClosedAt = t.AddHours(3) });
+            repo.Insert(new TradeRecord { Id = "c", ClosedAt = t.AddHours(2) });
+
+            var recent = repo.GetRecent(2);
+
+            Assert.Equal(2, recent.Count);
+            Assert.Equal("b", recent[0].Id);
+            Assert.Equal("c", recent[1].Id);
+        }
+
+        [Fact]
+        public void Find_filters_by_module_name()
+        {
+            var repo = NewRepo();
+            repo.Insert(new TradeRecord { Id = "a", ModuleName = "CopyTrading" });
+            repo.Insert(new TradeRecord { Id = "b", ModuleName = "Other" });
+
+            var ct = repo.Find(x => x.ModuleName == "CopyTrading");
+            Assert.Single(ct);
+            Assert.Equal("a", ct[0].Id);
+        }
+
+        [Fact]
+        public void Generated_id_is_unique_per_record()
+        {
+            var a = new TradeRecord();
+            var b = new TradeRecord();
+            Assert.False(string.IsNullOrEmpty(a.Id));
+            Assert.NotEqual(a.Id, b.Id);
+        }
+    }
+}