Personas have walls their followers write on

Owner decision of 2026-10-06 (G-0009, FEP-400e). A persona's actor names its wall (…/graffiti, sm:wall) and, in
Smithereen's privacySettings, that its followers may write on it. A public post that is not a reply, sent with the wall
as its target by an account following the persona, is hosted: the persona is notified, it reaches the persona's and its
followers' homes, and the followers' servers and the author's are told with Add{Note}. The persona deletes it with
DELETE /api/v1/statuses/:id, which sends Remove{Note}; Smithereen deletes the post then. The wall lists the persona's
public posts that start a thread and what was written on it.

Elsewhere: an account's Add{Note} on its own wall shows the post to its followers here as on that wall (privapub.wall on
the status), and its Remove takes it away. An Add or Remove naming a collection of the account's own server PrivaPub
does not know has its document read again first, at most hourly: accounts kept before walls were read had none.

Checked live: Smithereen 40 checks (G-0009 closed); GoToSocial and Mastodon unchanged (121).

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

PrivaPub/Api/Mastodon/Mappers/MastodonMapper.cs

@@ -203,7 +203,7 @@ namespace PrivaPub.Api.Mastodon.Mappers
 			var mentionAccounts = mentionUris.Count == 0
 				? new Dictionary<string, ForeignAvatar>()
 				: (await _dbEntities.ForeignAvatars.Match(f => mentionUris.Contains(f.ActorURI)).ExecuteAsync(token)).ToDictionary(f => f.ActorURI);
-			var accounts = await Accounts(all.Select(AuthorOf), token);
+			var accounts = await Accounts(all.Select(AuthorOf).Concat(all.Select(p => p.WallOwnerAccountId).Where(w => w != default)), token);
 
 			var ids = all.Select(p => p.ID).ToList();
 			var favourited = viewerId == default
@@ -277,7 +277,7 @@ namespace PrivaPub.Api.Mastodon.Mappers
 					Card = Card(post),
 					Poll = Poll(post, viewerId, ownVotes.GetValueOrDefault(post.ID)),
 					Emojis = Emojis(post.Emojis),
-					Privapub = Extension(post),
+					Privapub = Extension(post, accounts),
 					EmojiReactions = reactions.GetValueOrDefault(post.ID) ?? new(),
 					Pleroma = new PleromaStatus { EmojiReactions = reactions.GetValueOrDefault(post.ID) ?? new() },
 					Mentions = post.Mentions.Where(m => !m.Silent).Select(m => Mention(m, mentionAccounts)).Where(m => m != default).ToList(),
@@ -480,8 +480,9 @@ namespace PrivaPub.Api.Mastodon.Mappers
 		List<CustomEmojiEntity> Emojis(IEnumerable<CustomEmoji> emojis) =>
 			emojis?.Select(e => new CustomEmojiEntity { Shortcode = e.Shortcode, Url = Proxied(e.URL), StaticUrl = Proxied(e.URL) }).ToList() ?? new();
 
-		PrivaPubStatus Extension(PostEntity post) => new()
+		PrivaPubStatus Extension(PostEntity post, Dictionary<string, Account> accounts) => new()
 		{
+			Wall = post.WallOwnerAccountId == default || post.WallOwnerAccountId == AuthorOf(post) ? default : accounts.GetValueOrDefault(post.WallOwnerAccountId),
 			ObjectType = post.ObjectType,
 			Locked = post.LockedAt.HasValue,
 			Approval = post.Approval is ApprovalState.Pending or ApprovalState.Rejected ? post.Approval.ToString().ToLowerInvariant() : default,