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/Authority/StellaOps.Authority/StellaOps.Auth.Client/README.NuGet.md

@@ -5,5 +5,7 @@ Typed OpenID Connect client used by StellaOps services, agents, and tooling to t
 - Discovery + JWKS caching with deterministic refresh windows.
 - Password and client-credential flows with token cache abstractions.
 - Configurable HTTP retry/backoff policies (Polly) and offline fallback support for air-gapped deployments.
+- `HttpClient` authentication helpers that attach OAuth2 (password/client-credentials) or personal access tokens,
+  including automatic `X-StellaOps-Tenant` header injection for multi-tenant APIs.
 
 See `docs/dev/32_AUTH_CLIENT_GUIDE.md` in the repository for integration guidance, option descriptions, and rollout checklists.