feat: Implement MongoDB orchestrator storage with registry, commands, and heartbeats

- Added NullAdvisoryObservationEventTransport for handling advisory observation events.
- Created IOrchestratorRegistryStore interface for orchestrator registry operations.
- Implemented MongoOrchestratorRegistryStore for MongoDB interactions with orchestrator data.
- Defined OrchestratorCommandDocument and OrchestratorCommandRecord for command handling.
- Added OrchestratorHeartbeatDocument and OrchestratorHeartbeatRecord for heartbeat tracking.
- Created OrchestratorRegistryDocument and OrchestratorRegistryRecord for registry management.
- Developed tests for orchestrator collections migration and MongoOrchestratorRegistryStore functionality.
- Introduced AirgapImportRequest and AirgapImportValidator for air-gapped VEX bundle imports.
- Added incident mode rules sample JSON for notifier configuration.

src/Concelier/StellaOps.Concelier.WebService/Contracts/AdvisoryRawContracts.cs

@@ -1,8 +1,9 @@
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.Text.Json;
-using System.Text.Json.Serialization;
-using StellaOps.Concelier.RawModels;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using StellaOps.Concelier.Core.Attestation;
+using StellaOps.Concelier.RawModels;
 
 namespace StellaOps.Concelier.WebService.Contracts;
 
@@ -89,7 +90,8 @@ public sealed record AdvisoryRawListResponse(
 
 public sealed record AdvisoryEvidenceResponse(
     [property: JsonPropertyName("advisoryKey")] string AdvisoryKey,
-    [property: JsonPropertyName("records")] IReadOnlyList<AdvisoryRawRecordResponse> Records);
+    [property: JsonPropertyName("records")] IReadOnlyList<AdvisoryRawRecordResponse> Records,
+    [property: JsonPropertyName("attestation")] AttestationClaims? Attestation);
 
 public sealed record AdvisoryRawProvenanceResponse(
     [property: JsonPropertyName("id")] string Id,