Add Authority Advisory AI and API Lifecycle Configuration

- Introduced AuthorityAdvisoryAiOptions and related classes for managing advisory AI configurations, including remote inference options and tenant-specific settings.
- Added AuthorityApiLifecycleOptions to control API lifecycle settings, including legacy OAuth endpoint configurations.
- Implemented validation and normalization methods for both advisory AI and API lifecycle options to ensure proper configuration.
- Created AuthorityNotificationsOptions and its related classes for managing notification settings, including ack tokens, webhooks, and escalation options.
- Developed IssuerDirectoryClient and related models for interacting with the issuer directory service, including caching mechanisms and HTTP client configurations.
- Added support for dependency injection through ServiceCollectionExtensions for the Issuer Directory Client.
- Updated project file to include necessary package references for the new Issuer Directory Client library.

src/Excititor/StellaOps.Excititor.Worker/Program.cs

@@ -17,6 +17,7 @@ using StellaOps.Excititor.Worker.Scheduling;
 using StellaOps.Excititor.Worker.Signature;
 using StellaOps.Excititor.Attestation.Extensions;
 using StellaOps.Excititor.Attestation.Verification;
+using StellaOps.IssuerDirectory.Client;
 
 var builder = Host.CreateApplicationBuilder(args);
 var services = builder.Services;
@@ -39,6 +40,15 @@ services.AddOpenVexNormalizer();
 services.AddSingleton<IVexSignatureVerifier, WorkerSignatureVerifier>();
 services.AddVexAttestation();
 services.Configure<VexAttestationVerificationOptions>(configuration.GetSection("Excititor:Attestation:Verification"));
+var issuerDirectorySection = configuration.GetSection("Excititor:IssuerDirectory");
+if (issuerDirectorySection.Exists())
+{
+    services.AddIssuerDirectoryClient(issuerDirectorySection);
+}
+else
+{
+    services.AddIssuerDirectoryClient(configuration);
+}
 services.PostConfigure<VexAttestationVerificationOptions>(options =>
 {
     // Workers operate in offline-first environments; allow verification to succeed without Rekor.