Improved mailboxes to include sent mails and drafts (#1038)

app/MindWork AI Studio/Tools/Services/MailboxCoverage.cs

@@ -5,7 +5,7 @@ namespace AIStudio.Tools.Services;
 /// <summary>
 /// How far the index of a mailbox reaches, so that an answer from it can say what it does not cover.
 /// </summary>
-/// <param name="ReceivedSinceUtc">Since when mails are indexed, or null when all of them are. Flagged mails are indexed regardless of their age.</param>
+/// <param name="ReceivedSinceUtc">Since when mails are indexed, or null when all of them are. Flagged mails and drafts are indexed regardless of their age.</param>
 /// <param name="LastCompleteSyncUtc">When the last complete sync ended, or null while the first one is still running.</param>
 /// <param name="SignInRefusedAtUtc">When the server refused to let AI Studio sign in, or null when it did not. Until the user deals with that, no new mail arrives in the index.</param>
 /// <param name="PendingRemovalCount">How many mails the index still holds although a sync would have removed them, waiting for the user to agree, or null when there are none.</param>