refactor(dotnet): centralize runtime audit trail

src/dotnet/QuantEngine.Core.Tests/FactorComputationServiceTests.cs

@@ -2,6 +2,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Threading.Tasks;
 using Moq;
+using QuantEngine.Application.Interfaces;
 using QuantEngine.Application.Services;
 using QuantEngine.Core.Domain;
 using QuantEngine.Core.Interfaces;
@@ -15,39 +16,17 @@ public class FactorComputationServiceTests
     public async Task ComputeAndAppendFactorOutputs_WritesAuditAndHistory()
     {
         var storeMock = new Mock<IPostgresqlHistoryStore>();
+        var auditTrailMock = new Mock<IRuntimeAuditTrailService>();
         storeMock.Setup(s => s.AppendAsync(It.IsAny<string>(), It.IsAny<IDictionary<string, object?>>()))
             .ReturnsAsync(1);
 
         var history = new HistoryIngestionService(storeMock.Object);
-        var service = new FactorComputationService(history);
-
-        var root = FindRepoRoot();
-        var auditPath = Path.Combine(root, "Temp", "factor_audit", "005930.jsonl");
-        if (File.Exists(auditPath))
-        {
-            File.Delete(auditPath);
-        }
+        var service = new FactorComputationService(history, auditTrailMock.Object);
 
         var outputs = new FactorOutputs(1, 2, 3, 4, 5, 6, 7);
         await service.AppendFactorOutputsAsync("005930", "v1", outputs);
 
         storeMock.Verify(s => s.AppendAsync("factor_output_history", It.IsAny<IDictionary<string, object?>>()), Times.Exactly(7));
-        Assert.True(File.Exists(auditPath));
-        Assert.Contains("PERSISTED", File.ReadAllText(auditPath));
-    }
-
-    private static string FindRepoRoot()
-    {
-        var current = new DirectoryInfo(System.AppContext.BaseDirectory);
-        while (current != null)
-        {
-            if (Directory.Exists(Path.Combine(current.FullName, ".git")))
-            {
-                return current.FullName;
-            }
-            current = current.Parent;
-        }
-
-        throw new InvalidOperationException("Repository root not found.");
+        auditTrailMock.Verify(a => a.Append("factor_audit", "005930", It.IsAny<FactorComputationAudit>()), Times.Once);
     }
 }