feat: Enhance MongoDB storage with event publishing and outbox support

- Added `MongoAdvisoryObservationEventPublisher` and `NatsAdvisoryObservationEventPublisher` for event publishing.
- Registered `IAdvisoryObservationEventPublisher` to choose between NATS and MongoDB based on configuration.
- Introduced `MongoAdvisoryObservationEventOutbox` for outbox pattern implementation.
- Updated service collection to include new event publishers and outbox.
- Added a new hosted service `AdvisoryObservationTransportWorker` for processing events.

feat: Update project dependencies

- Added `NATS.Client.Core` package to the project for NATS integration.

test: Add unit tests for AdvisoryLinkset normalization

- Created `AdvisoryLinksetNormalizationConfidenceTests` to validate confidence score calculations.

fix: Adjust confidence assertion in `AdvisoryObservationAggregationTests`

- Updated confidence assertion to allow a range instead of a fixed value.

test: Implement tests for AdvisoryObservationEventFactory

- Added `AdvisoryObservationEventFactoryTests` to ensure correct mapping and hashing of observation events.

chore: Configure test project for Findings Ledger

- Created `Directory.Build.props` for test project configuration.
- Added `StellaOps.Findings.Ledger.Exports.Unit.csproj` for unit tests related to findings ledger exports.

feat: Implement export contracts for findings ledger

- Defined export request and response contracts in `ExportContracts.cs`.
- Created various export item records for findings, VEX, advisories, and SBOMs.

feat: Add export functionality to Findings Ledger Web Service

- Implemented endpoints for exporting findings, VEX, advisories, and SBOMs.
- Integrated `ExportQueryService` for handling export logic and pagination.

test: Add tests for Node language analyzer phase 22

- Implemented `NodePhase22SampleLoaderTests` to validate loading of NDJSON fixtures.
- Created sample NDJSON file for testing.

chore: Set up isolated test environment for Node tests

- Added `node-isolated.runsettings` for isolated test execution.
- Created `node-tests-isolated.sh` script for running tests in isolation.

src/Concelier/__Libraries/StellaOps.Concelier.Storage.Mongo/ServiceCollectionExtensions.cs

@@ -79,6 +79,19 @@ public static class ServiceCollectionExtensions
         services.AddSingleton<IAdvisoryObservationLookup, AdvisoryObservationLookup>();
         services.AddSingleton<IAdvisoryEventRepository, MongoAdvisoryEventRepository>();
         services.AddSingleton<IAdvisoryEventLog, AdvisoryEventLog>();
+        services.AddSingleton<MongoAdvisoryObservationEventPublisher>();
+        services.AddSingleton<NatsAdvisoryObservationEventPublisher>();
+        services.AddSingleton<IAdvisoryObservationEventPublisher>(sp =>
+        {
+            var options = sp.GetRequiredService<IOptions<AdvisoryObservationEventPublisherOptions>>().Value;
+            if (string.Equals(options.Transport, "nats", StringComparison.OrdinalIgnoreCase))
+            {
+                return sp.GetRequiredService<NatsAdvisoryObservationEventPublisher>();
+            }
+
+            return sp.GetRequiredService<MongoAdvisoryObservationEventPublisher>();
+        });
+        services.AddSingleton<IAdvisoryObservationEventOutbox, MongoAdvisoryObservationEventOutbox>();
         services.AddSingleton<IAdvisoryRawRepository, MongoAdvisoryRawRepository>();
         services.AddSingleton<StellaOps.Concelier.Storage.Mongo.Linksets.IMongoAdvisoryLinksetStore, StellaOps.Concelier.Storage.Mongo.Linksets.ConcelierMongoLinksetStore>();
         services.AddSingleton<StellaOps.Concelier.Core.Linksets.IAdvisoryLinksetStore>(sp =>
@@ -108,6 +121,12 @@ public static class ServiceCollectionExtensions
             return database.GetCollection<AdvisoryObservationDocument>(MongoStorageDefaults.Collections.AdvisoryObservations);
         });
 
+        services.AddSingleton<IMongoCollection<AdvisoryObservationEventDocument>>(static sp =>
+        {
+            var database = sp.GetRequiredService<IMongoDatabase>();
+            return database.GetCollection<AdvisoryObservationEventDocument>(MongoStorageDefaults.Collections.AdvisoryObservationEvents);
+        });
+
         services.AddSingleton<IMongoCollection<AdvisoryLinksetDocument>>(static sp =>
         {
             var database = sp.GetRequiredService<IMongoDatabase>();
@@ -126,8 +145,11 @@ public static class ServiceCollectionExtensions
         services.AddSingleton<IMongoMigration, EnsureAdvisoryObservationsRawLinksetMigration>();
         services.AddSingleton<IMongoMigration, EnsureAdvisoryLinksetsTenantLowerMigration>();
         services.AddSingleton<IMongoMigration, EnsureAdvisoryEventCollectionsMigration>();
+        services.AddSingleton<IMongoMigration, EnsureAdvisoryObservationEventCollectionMigration>();
         services.AddSingleton<IMongoMigration, SemVerStyleBackfillMigration>();
 
+        services.AddSingleton<IHostedService, AdvisoryObservationTransportWorker>();
+
         return services;
     }
 }