Follow requests asked again, and followed accounts found by name

A server can take a Follow with 202 and drop it afterwards, as Pleroma does
while it cannot fetch our actor; the request then stayed pending for good.
Following again now sends an unanswered request once more, the same
activity, at most once an hour (a delivery's `again` key).

accounts/search takes following=true: only accounts the persona follows,
by the start of their name, display name or server, never resolved; a
client fills a list with it. "already take" becomes "already taken".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

PrivaPub/Domain/Social/FollowService.cs

@@ -105,6 +105,11 @@ namespace PrivaPub.Domain.Social
 				if (existing.ShowReblogs != showReblogs)
 					await DB.Default.Update<Following>().MatchID(existing.ID).Modify(f => f.ShowReblogs, showReblogs).ExecuteAsync(token);
 				existing.ShowReblogs = showReblogs;
+				// a request still unanswered is sent again, at most once an hour: a server can take a Follow (202) and
+				// drop it later, as one that cannot yet read our actor does; one that holds it already ignores the copy
+				if (existing.State == FollowState.Requested && remote != default)
+					await _delivery.Enqueue(follower, new[] { remote.InboxURL }, FollowActivity(follower, existing), token,
+						again: "again-" + DateTime.UtcNow.ToString("yyyyMMddHH", System.Globalization.CultureInfo.InvariantCulture));
 				return existing;
 			}