A status asked for by id is shown, and remote warnings are their own

GET /api/v1/statuses/:id applied the viewer's own blocks and mutes and
answered 200 with null for a post of an author the viewer had blocked;
decePub's thread page then showed nothing. As in Mastodon, a status asked
for by id (or acted on) is shown whatever the viewer blocked or muted,
and only lists leave such posts out; when nothing can be shown the
answer is 404, never null, and search leaves it out.

A remote post marked sensitive with an empty summary (Akkoma's sensitive
media, Lemmy's NSFW) got an invented "Content warning" that hid its
words. A remote post now keeps its own summary: sensitive without one
hides the media only. A local post warned without words still gets the
default warning.

Both found by decePub's end-to-end tests on the town.

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

PrivaPub/Api/Mastodon/Mappers/MastodonMapper.cs

@@ -146,12 +146,15 @@ namespace PrivaPub.Api.Mastodon.Mappers
 		}
 
 		public async Task<Status> Status(PostEntity post, string viewerId, CancellationToken token) =>
-			(await Statuses(new[] { post }, viewerId, token)).FirstOrDefault();
+			(await Statuses(new[] { post }, viewerId, nested: false, token, hideFromViewer: false)).FirstOrDefault();
 
 		public Task<List<Status>> Statuses(IReadOnlyCollection<PostEntity> posts, string viewerId, CancellationToken token) =>
 			Statuses(posts, viewerId, nested: false, token);
 
-		async Task<List<Status>> Statuses(IReadOnlyCollection<PostEntity> posts, string viewerId, bool nested, CancellationToken token)
+		// Lists leave out what the viewer blocked or muted; a status asked for by its id is still shown, as Mastodon shows it
+		// (only its author's block of the viewer hides it, and that is decided before mapping)
+		async Task<List<Status>> Statuses(IReadOnlyCollection<PostEntity> posts, string viewerId, bool nested, CancellationToken token,
+			bool hideFromViewer = true)
 		{
 			var originalIds = posts.Where(p => p.ReblogOfPostId != default).Select(p => p.ReblogOfPostId).Distinct().ToList();
 			var originals = originalIds.Count == 0
@@ -191,7 +194,7 @@ namespace PrivaPub.Api.Mastodon.Mappers
 				? new Dictionary<string, List<int>>()
 				: (await DB.Default.Find<PollVote>().Match(v => pollIds.Contains(v.PostId) && v.VoterAccountId == viewerId && v.IsLocalVoter).ExecuteAsync(token))
 					.GroupBy(v => v.PostId).ToDictionary(g => g.Key, g => g.Select(v => v.Choice).ToList());
-			var hidden = viewerId == default
+			var hidden = viewerId == default || !hideFromViewer
 				? new HashSet<string>()
 				: await Domain.Relationships.Hidden.AuthorsHiddenFrom(viewerId, all.Select(p => p.ActorURI), forNotifications: false, token);
 			var reblogged = viewerId == default
@@ -222,7 +225,9 @@ namespace PrivaPub.Api.Mastodon.Mappers
 					Bookmarked = bookmarked.Contains(post.ID),
 					Pinned = pinned.Contains(post.ID),
 					Sensitive = post.HasContentWarning,
-					SpoilerText = post.SpoilerText ?? (post.HasContentWarning ? post.Title ?? ActivityPubRenderer.ContentWarning : string.Empty),
+					//a remote post keeps its own summary: sensitive with none (Akkoma's sensitive media, Lemmy's NSFW) hides the
+					//media, never the words behind an invented warning; a local post warned without words gets the default one
+					SpoilerText = post.SpoilerText ?? (post.HasContentWarning && !post.IsFederatedCopy ? post.Title ?? ActivityPubRenderer.ContentWarning : string.Empty),
 					Visibility = Visibility(post.Visibility),
 					Language = post.Language,
 					MediaAttachments = post.Media.Count > 0 ? post.Media.Select(Media).ToList() : Playable(post),