Add determinism tests for verdict artifact generation and update SHA256 sums script

- Implemented comprehensive tests for verdict artifact generation to ensure deterministic outputs across various scenarios, including identical inputs, parallel execution, and change ordering.
- Created helper methods for generating sample verdict inputs and computing canonical hashes.
- Added tests to validate the stability of canonical hashes, proof spine ordering, and summary statistics.
- Introduced a new PowerShell script to update SHA256 sums for files, ensuring accurate hash generation and file integrity checks.

src/Attestor/StellaOps.Attestor/StellaOps.Attestor.WebService/Program.cs

@@ -29,6 +29,7 @@ using StellaOps.Attestor.Core.Bulk;
 using Microsoft.AspNetCore.Server.Kestrel.Https;
 using Serilog.Context;
 using StellaOps.Cryptography.DependencyInjection;
+using StellaOps.Router.AspNet;
 
 const string ConfigurationSection = "attestor";
 
@@ -326,6 +327,13 @@ builder.WebHost.ConfigureKestrel(kestrel =>
     });
 });
 
+// Stella Router integration
+var routerOptions = builder.Configuration.GetSection("Attestor:Router").Get<StellaRouterOptionsBase>();
+builder.Services.TryAddStellaRouter(
+    serviceName: "attestor",
+    version: typeof(Program).Assembly.GetName().Version?.ToString() ?? "1.0.0",
+    routerOptions: routerOptions);
+
 var app = builder.Build();
 
 app.UseSerilogRequestLogging();
@@ -359,6 +367,7 @@ app.UseRateLimiter();
 
 app.UseAuthentication();
 app.UseAuthorization();
+app.TryUseStellaRouter(routerOptions);
 
 app.MapHealthChecks("/health/ready");
 app.MapHealthChecks("/health/live");
@@ -608,6 +617,9 @@ app.MapGet("/api/v1/rekor/verify:bulk/{jobId}", async (
     return Results.Ok(BulkVerificationContracts.MapJob(job));
 }).RequireAuthorization("attestor:write");
 
+// Refresh Router endpoint cache
+app.TryRefreshStellaRouterEndpoints(routerOptions);
+
 app.Run();
 
 static async Task<IResult> GetAttestationDetailResultAsync(

src/Attestor/StellaOps.Attestor/StellaOps.Attestor.WebService/StellaOps.Attestor.WebService.csproj

@@ -27,5 +27,6 @@
     <ProjectReference Include="../../../Authority/StellaOps.Authority/StellaOps.Auth.Client/StellaOps.Auth.Client.csproj" />
     <ProjectReference Include="../../../Authority/StellaOps.Authority/StellaOps.Auth.ServerIntegration/StellaOps.Auth.ServerIntegration.csproj" />
     <ProjectReference Include="../../__Libraries/StellaOps.Attestor.StandardPredicates/StellaOps.Attestor.StandardPredicates.csproj" />
+    <ProjectReference Include="../../../__Libraries/StellaOps.Router.AspNet/StellaOps.Router.AspNet.csproj" />
   </ItemGroup>
 </Project>