Add new features and tests for AirGap and Time modules

- Introduced `SbomService` tasks documentation.
- Updated `StellaOps.sln` to include new projects: `StellaOps.AirGap.Time` and `StellaOps.AirGap.Importer`.
- Added unit tests for `BundleImportPlanner`, `DsseVerifier`, `ImportValidator`, and other components in the `StellaOps.AirGap.Importer.Tests` namespace.
- Implemented `InMemoryBundleRepositories` for testing bundle catalog and item repositories.
- Created `MerkleRootCalculator`, `RootRotationPolicy`, and `TufMetadataValidator` tests.
- Developed `StalenessCalculator` and `TimeAnchorLoader` tests in the `StellaOps.AirGap.Time.Tests` namespace.
- Added `fetch-sbomservice-deps.sh` script for offline dependency fetching.

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

@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
+
+namespace StellaOps.Concelier.WebService.Contracts;
+
+public sealed record LnmLinksetResponse(
+    [property: JsonPropertyName("advisoryId")] string AdvisoryId,
+    [property: JsonPropertyName("source")] string Source,
+    [property: JsonPropertyName("observations")] IReadOnlyList<string> Observations,
+    [property: JsonPropertyName("normalized")] LnmLinksetNormalized? Normalized,
+    [property: JsonPropertyName("conflicts")] IReadOnlyList<LnmLinksetConflict>? Conflicts,
+    [property: JsonPropertyName("provenance")] LnmLinksetProvenance? Provenance,
+    [property: JsonPropertyName("createdAt")] DateTimeOffset CreatedAt,
+    [property: JsonPropertyName("builtByJobId")] string? BuiltByJobId,
+    [property: JsonPropertyName("cached")] bool Cached);
+
+public sealed record LnmLinksetNormalized(
+    [property: JsonPropertyName("purls")] IReadOnlyList<string>? Purls,
+    [property: JsonPropertyName("versions")] IReadOnlyList<string>? Versions,
+    [property: JsonPropertyName("ranges")] IReadOnlyList<object>? Ranges,
+    [property: JsonPropertyName("severities")] IReadOnlyList<object>? Severities);
+
+public sealed record LnmLinksetConflict(
+    [property: JsonPropertyName("field")] string Field,
+    [property: JsonPropertyName("reason")] string Reason,
+    [property: JsonPropertyName("values")] IReadOnlyList<string>? Values);
+
+public sealed record LnmLinksetProvenance(
+    [property: JsonPropertyName("observationHashes")] IReadOnlyList<string>? ObservationHashes,
+    [property: JsonPropertyName("toolVersion")] string? ToolVersion,
+    [property: JsonPropertyName("policyHash")] string? PolicyHash);
+
+public sealed record LnmLinksetQuery(
+    [Required]
+    [property: JsonPropertyName("advisoryId")] string AdvisoryId,
+    [Required]
+    [property: JsonPropertyName("source")] string Source,
+    [property: JsonPropertyName("includeConflicts")] bool IncludeConflicts = true);