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.Scanner.WebService/Services/ScanProgressStream.cs

@@ -1,7 +1,6 @@
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Threading.Channels;
 using StellaOps.Scanner.WebService.Domain;
@@ -58,7 +57,8 @@ public sealed class ScanProgressStream : IScanProgressPublisher, IScanProgressRe
         public int NextSequence() => ++Sequence;
     }
 
-    private static readonly IReadOnlyDictionary<string, object?> EmptyData = new ReadOnlyDictionary<string, object?>(new Dictionary<string, object?>(StringComparer.OrdinalIgnoreCase));
+    private static readonly IReadOnlyDictionary<string, object?> EmptyData =
+        new ReadOnlyDictionary<string, object?>(new SortedDictionary<string, object?>(StringComparer.OrdinalIgnoreCase));
 
     private readonly ConcurrentDictionary<string, ProgressChannel> channels = new(StringComparer.OrdinalIgnoreCase);
     private readonly TimeProvider timeProvider;
@@ -85,18 +85,14 @@ public sealed class ScanProgressStream : IScanProgressPublisher, IScanProgressRe
         {
             var sequence = channel.NextSequence();
             var correlation = correlationId ?? $"{scanId.Value}:{sequence:D4}";
-            var payload = data is null || data.Count == 0
-                ? EmptyData
-                : new ReadOnlyDictionary<string, object?>(new Dictionary<string, object?>(data, StringComparer.OrdinalIgnoreCase));
-
-            progressEvent = new ScanProgressEvent(
-                scanId,
-                sequence,
-                timeProvider.GetUtcNow(),
-                state,
-                message,
-                correlation,
-                payload);
+            progressEvent = new ScanProgressEvent(
+                scanId,
+                sequence,
+                timeProvider.GetUtcNow(),
+                state,
+                message,
+                correlation,
+                NormalizePayload(data));
 
             channel.Append(progressEvent);
         }
@@ -131,6 +127,24 @@ public sealed class ScanProgressStream : IScanProgressPublisher, IScanProgressRe
             {
                 yield return progressEvent;
             }
-        }
-    }
-}
+        }
+    }
+
+    private static IReadOnlyDictionary<string, object?> NormalizePayload(IReadOnlyDictionary<string, object?>? data)
+    {
+        if (data is null || data.Count == 0)
+        {
+            return EmptyData;
+        }
+
+        var sorted = new SortedDictionary<string, object?>(StringComparer.OrdinalIgnoreCase);
+        foreach (var pair in data)
+        {
+            sorted[pair.Key] = pair.Value;
+        }
+
+        return sorted.Count == 0
+            ? EmptyData
+            : new ReadOnlyDictionary<string, object?>(sorted);
+    }
+}