Add unit tests for RabbitMq and Udp transport servers and clients

- Implemented comprehensive unit tests for RabbitMqTransportServer, covering constructor, disposal, connection management, event handlers, and exception handling.
- Added configuration tests for RabbitMqTransportServer to validate SSL, durable queues, auto-recovery, and custom virtual host options.
- Created unit tests for UdpFrameProtocol, including frame parsing and serialization, header size validation, and round-trip data preservation.
- Developed tests for UdpTransportClient, focusing on connection handling, event subscriptions, and exception scenarios.
- Established tests for UdpTransportServer, ensuring proper start/stop behavior, connection state management, and event handling.
- Included tests for UdpTransportOptions to verify default values and modification capabilities.
- Enhanced service registration tests for Udp transport services in the dependency injection container.

src/Scanner/__Libraries/StellaOps.Scanner.Reachability/RichGraphWriter.cs

@@ -1,20 +1,24 @@
 using System;
-using System.Collections.Generic;
 using System.IO;
-using System.Linq;
-using System.Security.Cryptography;
-using System.Text;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
+using StellaOps.Cryptography;
 
 namespace StellaOps.Scanner.Reachability;
 
 /// <summary>
-/// Writes richgraph-v1 documents to disk with canonical ordering and BLAKE3 hash.
+/// Writes richgraph-v1 documents to disk with canonical ordering and compliance-profile-aware hashing.
+/// Uses <see cref="HashPurpose.Graph"/> for content addressing, which resolves to:
+/// - BLAKE3-256 for "world" profile
+/// - SHA-256 for "fips" profile
+/// - GOST3411-2012-256 for "gost" profile
+/// - SM3 for "sm" profile
 /// </summary>
 public sealed class RichGraphWriter
 {
+    private readonly ICryptoHash _cryptoHash;
+
     private static readonly JsonWriterOptions JsonOptions = new()
     {
         Encoder = System.Text.Encodings.Web.JavaScriptEncoder.UnsafeRelaxedJsonEscaping,
@@ -22,6 +26,15 @@ public sealed class RichGraphWriter
         SkipValidation = false
     };
 
+    /// <summary>
+    /// Creates a new RichGraphWriter with the specified crypto hash service.
+    /// </summary>
+    /// <param name="cryptoHash">Crypto hash service for compliance-aware hashing.</param>
+    public RichGraphWriter(ICryptoHash cryptoHash)
+    {
+        _cryptoHash = cryptoHash ?? throw new ArgumentNullException(nameof(cryptoHash));
+    }
+
     public async Task<RichGraphWriteResult> WriteAsync(
         RichGraph graph,
         string outputRoot,
@@ -46,7 +59,7 @@ public sealed class RichGraphWriter
         }
 
         var bytes = await File.ReadAllBytesAsync(graphPath, cancellationToken).ConfigureAwait(false);
-        var graphHash = ComputeSha256(bytes);
+        var graphHash = _cryptoHash.ComputePrefixedHashForPurpose(bytes, HashPurpose.Graph);
 
         var metaPath = Path.Combine(root, "meta.json");
         await using (var stream = File.Create(metaPath))
@@ -169,12 +182,6 @@ public sealed class RichGraphWriter
         writer.WriteEndObject();
     }
 
-    private static string ComputeSha256(IReadOnlyList<byte> bytes)
-    {
-        using var sha = SHA256.Create();
-        var hash = sha.ComputeHash(bytes.ToArray());
-        return "sha256:" + Convert.ToHexString(hash).ToLowerInvariant();
-    }
 }
 
 public sealed record RichGraphWriteResult(