Add Windows share target draft attachment flow

Wino.Core.Domain/Models/Launch/PendingComposeMailShareRequest.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace Wino.Core.Domain.Models.Launch;
+
+public sealed class PendingComposeMailShareRequest
+{
+    public PendingComposeMailShareRequest(Guid draftUniqueId, MailShareRequest shareRequest)
+    {
+        DraftUniqueId = draftUniqueId;
+        ShareRequest = shareRequest ?? throw new ArgumentNullException(nameof(shareRequest));
+    }
+
+    public Guid DraftUniqueId { get; }
+    public MailShareRequest ShareRequest { get; }
+}