Add channel test providers for Email, Slack, Teams, and Webhook

- Implemented EmailChannelTestProvider to generate email preview payloads.
- Implemented SlackChannelTestProvider to create Slack message previews.
- Implemented TeamsChannelTestProvider for generating Teams Adaptive Card previews.
- Implemented WebhookChannelTestProvider to create webhook payloads.
- Added INotifyChannelTestProvider interface for channel-specific preview generation.
- Created ChannelTestPreviewContracts for request and response models.
- Developed NotifyChannelTestService to handle test send requests and generate previews.
- Added rate limit policies for test sends and delivery history.
- Implemented unit tests for service registration and binding.
- Updated project files to include necessary dependencies and configurations.

src/StellaOps.Concelier.Exporter.Json/JsonExportResult.cs

@@ -1,46 +1,55 @@
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.Linq;
-
-namespace StellaOps.Concelier.Exporter.Json;
-
-public sealed class JsonExportResult
-{
-    public JsonExportResult(
-        string exportDirectory,
-        DateTimeOffset exportedAt,
-        IEnumerable<JsonExportFile> files,
-        int advisoryCount,
-        long totalBytes)
-    {
-        if (string.IsNullOrWhiteSpace(exportDirectory))
-        {
-            throw new ArgumentException("Export directory must be provided.", nameof(exportDirectory));
-        }
-
-        ExportDirectory = exportDirectory;
-        ExportedAt = exportedAt;
-        AdvisoryCount = advisoryCount;
-        TotalBytes = totalBytes;
-
-        var list = (files ?? throw new ArgumentNullException(nameof(files)))
-            .Where(static file => file is not null)
-            .ToImmutableArray();
-
-        Files = list;
-        FilePaths = list.Select(static file => file.RelativePath).ToImmutableArray();
-    }
-
-    public string ExportDirectory { get; }
-
-    public DateTimeOffset ExportedAt { get; }
-
-    public ImmutableArray<JsonExportFile> Files { get; }
-
-    public ImmutableArray<string> FilePaths { get; }
-
-    public int AdvisoryCount { get; }
-
-    public long TotalBytes { get; }
-}
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+using StellaOps.Concelier.Models;
+
+namespace StellaOps.Concelier.Exporter.Json;
+
+public sealed class JsonExportResult
+{
+    public JsonExportResult(
+        string exportDirectory,
+        DateTimeOffset exportedAt,
+        IEnumerable<JsonExportFile> files,
+        int advisoryCount,
+        long totalBytes,
+        IEnumerable<Advisory>? advisories = null)
+    {
+        if (string.IsNullOrWhiteSpace(exportDirectory))
+        {
+            throw new ArgumentException("Export directory must be provided.", nameof(exportDirectory));
+        }
+
+        var list = (files ?? throw new ArgumentNullException(nameof(files)))
+            .Where(static file => file is not null)
+            .ToImmutableArray();
+
+        var advisoryList = (advisories ?? Array.Empty<Advisory>())
+            .Where(static advisory => advisory is not null)
+            .ToImmutableArray();
+
+        ExportDirectory = exportDirectory;
+        ExportedAt = exportedAt;
+        TotalBytes = totalBytes;
+
+        Files = list;
+        FilePaths = list.Select(static file => file.RelativePath).ToImmutableArray();
+        Advisories = advisoryList;
+        AdvisoryCount = advisoryList.IsDefaultOrEmpty ? advisoryCount : advisoryList.Length;
+    }
+
+    public string ExportDirectory { get; }
+
+    public DateTimeOffset ExportedAt { get; }
+
+    public ImmutableArray<JsonExportFile> Files { get; }
+
+    public ImmutableArray<string> FilePaths { get; }
+
+    public ImmutableArray<Advisory> Advisories { get; }
+
+    public int AdvisoryCount { get; }
+
+    public long TotalBytes { get; }
+}