Add tests for SBOM generation determinism across multiple formats

- Created `StellaOps.TestKit.Tests` project for unit tests related to determinism.
- Implemented `DeterminismManifestTests` to validate deterministic output for canonical bytes and strings, file read/write operations, and error handling for invalid schema versions.
- Added `SbomDeterminismTests` to ensure identical inputs produce consistent SBOMs across SPDX 3.0.1 and CycloneDX 1.6/1.7 formats, including parallel execution tests.
- Updated project references in `StellaOps.Integration.Determinism` to include the new determinism testing library.

src/Scheduler/__Libraries/StellaOps.Scheduler.ImpactIndex/Fixtures/sample.bom-index.json

@@ -1,23 +0,0 @@
-{
-  "schema": "scheduler-impact-index@1",
-  "generatedAt": "2025-10-01T00:00:00Z",
-  "image": {
-    "repository": "registry.stellaops.test/team/sample-service",
-    "digest": "sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef",
-    "tag": "1.0.0"
-  },
-  "components": [
-    {
-      "purl": "pkg:docker/sample-service@1.0.0",
-      "usage": [
-        "runtime"
-      ]
-    },
-    {
-      "purl": "pkg:pypi/requests@2.31.0",
-      "usage": [
-        "usedByEntrypoint"
-      ]
-    }
-  ]
-}

src/Scheduler/__Libraries/StellaOps.Scheduler.ImpactIndex/RoaringImpactIndex.cs

@@ -3,11 +3,11 @@ using System.Buffers.Binary;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
-using System.Security.Cryptography;
 using System.Text;
 using System.Text.RegularExpressions;
 using Collections.Special;
 using Microsoft.Extensions.Logging;
+using StellaOps.Cryptography;
 using StellaOps.Scheduler.ImpactIndex.Ingestion;
 using StellaOps.Scheduler.Models;
 
@@ -18,6 +18,7 @@ namespace StellaOps.Scheduler.ImpactIndex;
 /// </summary>
 public sealed class RoaringImpactIndex : IImpactIndex
 {
+    private static readonly ICryptoHash Hash = CryptoHashFactory.CreateDefault();
     private readonly object _gate = new();
 
     private readonly Dictionary<string, int> _imageIds = new(StringComparer.OrdinalIgnoreCase);
@@ -570,8 +571,8 @@ public sealed class RoaringImpactIndex : IImpactIndex
         AppendMap(contains);
         AppendMap(usedBy);
 
-        var hash = SHA256.HashData(Encoding.UTF8.GetBytes(builder.ToString()));
-        return "snap-" + Convert.ToHexString(hash).ToLowerInvariant();
+        var hashHex = Hash.ComputeHashHex(Encoding.UTF8.GetBytes(builder.ToString()), HashAlgorithms.Sha256);
+        return "snap-" + hashHex;
     }
 
     private static bool MatchesTagPattern(string tag, string pattern)
@@ -620,7 +621,7 @@ public sealed class RoaringImpactIndex : IImpactIndex
 
     private static int ComputeDeterministicId(string digest)
     {
-        var bytes = SHA256.HashData(Encoding.UTF8.GetBytes(digest));
+        var bytes = Hash.ComputeHash(Encoding.UTF8.GetBytes(digest), HashAlgorithms.Sha256);
         for (var offset = 0; offset <= bytes.Length - sizeof(int); offset += sizeof(int))
         {
             var value = BinaryPrimitives.ReadInt32LittleEndian(bytes.AsSpan(offset, sizeof(int))) & int.MaxValue;

src/Scheduler/__Libraries/StellaOps.Scheduler.ImpactIndex/StellaOps.Scheduler.ImpactIndex.csproj

@@ -6,10 +6,10 @@
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="../StellaOps.Scheduler.Models/StellaOps.Scheduler.Models.csproj" />
+    <ProjectReference Include="../../../__Libraries/StellaOps.Cryptography/StellaOps.Cryptography.csproj" />
   </ItemGroup>
   <ItemGroup>
-    <EmbeddedResource Include="Fixtures\**\*.json" />
-    <EmbeddedResource Include="..\..\samples\scanner\images\**\bom-index.json"
+    <EmbeddedResource Include="..\..\..\..\samples\scanner\images\**\bom-index.json"
                       Link="Fixtures\%(RecursiveDir)%(Filename)%(Extension)" />
   </ItemGroup>
   <ItemGroup>