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/Scanner/__Libraries/StellaOps.Scanner.Surface.Validation/SurfaceValidationResult.cs

@@ -0,0 +1,29 @@
+using System.Collections.Immutable;
+
+namespace StellaOps.Scanner.Surface.Validation;
+
+/// <summary>
+/// Aggregate outcome emitted after running all registered validators.
+/// </summary>
+public sealed record SurfaceValidationResult
+{
+    private SurfaceValidationResult(bool isSuccess, ImmutableArray<SurfaceValidationIssue> issues)
+    {
+        IsSuccess = isSuccess;
+        Issues = issues;
+    }
+
+    public bool IsSuccess { get; }
+
+    public ImmutableArray<SurfaceValidationIssue> Issues { get; }
+
+    public static SurfaceValidationResult Success()
+        => new(true, ImmutableArray<SurfaceValidationIssue>.Empty);
+
+    public static SurfaceValidationResult FromIssues(IEnumerable<SurfaceValidationIssue> issues)
+    {
+        var immutable = issues.ToImmutableArray();
+        var success = immutable.All(issue => issue.Severity != SurfaceValidationSeverity.Error);
+        return new SurfaceValidationResult(success, immutable);
+    }
+}