Add unit tests for PackRunAttestation and SealedInstallEnforcer

- Implement comprehensive tests for PackRunAttestationService, covering attestation generation, verification, and event emission.
- Add tests for SealedInstallEnforcer to validate sealed install requirements and enforcement logic.
- Introduce a MonacoLoaderService stub for testing purposes to prevent Monaco workers/styles from loading during Karma runs.

src/Excititor/StellaOps.Excititor.WebService/Program.cs

@@ -90,6 +90,9 @@ services.AddSingleton<IVexHashingService>(sp =>
 services.AddSingleton<IVexObservationProjectionService, VexObservationProjectionService>();
 services.AddScoped<IVexObservationQueryService, VexObservationQueryService>();
 
+// EXCITITOR-RISK-66-001: Risk feed service for Risk Engine integration
+services.AddScoped<StellaOps.Excititor.Core.RiskFeed.IRiskFeedService, StellaOps.Excititor.Core.RiskFeed.RiskFeedService>();
+
 var rekorSection = configuration.GetSection("Excititor:Attestation:Rekor");
 if (rekorSection.Exists())
 {
@@ -2323,6 +2326,9 @@ PolicyEndpoints.MapPolicyEndpoints(app);
 ObservationEndpoints.MapObservationEndpoints(app);
 LinksetEndpoints.MapLinksetEndpoints(app);
 
+// Risk Feed APIs (EXCITITOR-RISK-66-001)
+RiskFeedEndpoints.MapRiskFeedEndpoints(app);
+
 app.Run();
 
 internal sealed record ExcititorTimelineEvent(