A remote handle on its own domain, once that domain's WebFinger agrees (FEP-2c59)

An account on a server whose handles are not its host's (Mastodon's LOCAL_DOMAIN apart from WEB_DOMAIN) showed as
user@host. The actor's `webfinger` names the handle; its domain is kept once WebFinger there points back to the actor,
and asked again when the name changes. A persona's blocked servers match a handle's domain as well as the actor's host,
as the lists Mastodon exports name handles' domains.

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

PrivaPub/Federation/Actors/ActorDocument.cs

@@ -25,6 +25,7 @@ namespace PrivaPub.Federation.Actors
 		public string Following { get; init; }
 		public string Featured { get; init; }
 		public string Wall { get; init; }
+		public string WebFinger { get; init; }//FEP-2c59: its handle, user@domain, where the domain is not its host's
 		public string SharedInbox { get; init; }
 		public string Icon { get; init; }
 		public bool Discoverable { get; init; } = true;
@@ -78,6 +79,7 @@ namespace PrivaPub.Federation.Actors
 				Following = RemoteActorService.Text(root, "following"),
 				Featured = RemoteActorService.Text(root, "featured"),
 				Wall = RemoteActorService.Text(root, "wall") ?? RemoteActorService.Text(root, "sm:wall"),
+				WebFinger = RemoteActorService.Text(root, "webfinger")?.Replace("acct:", "", StringComparison.OrdinalIgnoreCase).TrimStart('@'),
 				SharedInbox = root.TryGetProperty("endpoints", out var endpoints) ? RemoteActorService.Text(endpoints, "sharedInbox") : default,
 				Icon = root.TryGetProperty("icon", out var icon) ? RemoteActorService.Text(icon, "url") : default,
 				Discoverable = !root.TryGetProperty("discoverable", out var discoverable) || discoverable.ValueKind != JsonValueKind.False,