Add tests and implement StubBearer authentication for Signer endpoints

- Created SignerEndpointsTests to validate the SignDsse and VerifyReferrers endpoints.
- Implemented StubBearerAuthenticationDefaults and StubBearerAuthenticationHandler for token-based authentication.
- Developed ConcelierExporterClient for managing Trivy DB settings and export operations.
- Added TrivyDbSettingsPageComponent for UI interactions with Trivy DB settings, including form handling and export triggering.
- Implemented styles and HTML structure for Trivy DB settings page.
- Created NotifySmokeCheck tool for validating Redis event streams and Notify deliveries.

src/StellaOps.Cli/Configuration/StellaOpsCliOptions.cs

@@ -9,7 +9,7 @@ public sealed class StellaOpsCliOptions
     public string ApiKey { get; set; } = string.Empty;
 
     public string BackendUrl { get; set; } = string.Empty;
-
+
     public string ScannerCacheDirectory { get; set; } = "scanners";
 
     public string ResultsDirectory { get; set; } = "results";
@@ -23,6 +23,8 @@ public sealed class StellaOpsCliOptions
     public int ScanUploadAttempts { get; set; } = 3;
 
     public StellaOpsCliAuthorityOptions Authority { get; set; } = new();
+
+    public StellaOpsCliOfflineOptions Offline { get; set; } = new();
 }
 
 public sealed class StellaOpsCliAuthorityOptions
@@ -54,3 +56,10 @@ public sealed class StellaOpsCliAuthorityResilienceOptions
 
     public TimeSpan? OfflineCacheTolerance { get; set; }
 }
+
+public sealed class StellaOpsCliOfflineOptions
+{
+    public string KitsDirectory { get; set; } = "offline-kits";
+
+    public string? MirrorUrl { get; set; }
+}