Everything on, phase 4a: one answer everywhere for counts, search, collections and the instance API

Owner decision 2026-10-04: fix the mismatches and every other mismatch of the same kind.

- One counting rule (Domain/Privacy/Counted), Mastodon's. It is used for a persona's statuses_count, its outbox
  totalItems, NodeInfo localPosts and the instance status_count, which used to count four different things. It
  counts every post that is neither deleted nor a DM, boosts included, and circle and located posts too (owner
  decision). A group's count includes its remote members' posts.
- Users. Personas of banned or deleted roots no longer count, and are not found in search. NodeInfo now gives
  activeMonth and activeHalfyear, and the v2 instance gives active_month instead of a constant 0.
- replies_count counts only public and unlisted replies, so it no longer tells anyone that a private reply exists.
  Migration _012 recounts it.
- A remote account that deletes itself takes everything out of every count (GoneActors): its likes, downvotes,
  reactions and poll votes go and their counters come back, as do its boosts', replies' and quotes' counts, and its
  notifications. Lookups, account lists, search and favourited_by no longer show it. Migration _012 applies this to
  accounts already gone.
- Deleting a post also deletes its pins and the local boosts of it.
- /stalking gives the same total as following_count. Members are still never listed, and hide_collections is now
  always true, since the setting never did anything.
- Joining a community by invitation is following it, so /flock and /groupies agree; leaving unfollows.
- Search. Anyone may search, as on Mastodon; resolve and offset need a sign-in, offset pages, and deleted accounts
  are never found.
- notifications/unread_count counts what the list shows, and the owner's follower and following lists page with
  Link.
- The instance API advertises what is enforced:
  - max_characters, now enforced with a 422;
  - max_pinned_statuses = MaxPins;
  - the media types and limits MediaService and MediaOptions accept;
  - PollService's limits;
  - the configured languages;
  - no streaming URL until streaming exists.

  domain_count counts the servers we have exchanged with; which ones stays unpublished (peers is empty).
- Routes Mastodon answers now answer instead of 404:
  - directory, tags/{name}, timelines/link and identity_proofs;
  - instance/languages, translation_languages, domain_blocks and privacy_policy;
  - the v1 and v2 notification policy, and notification requests.

Also, from phase 3: a recovered password ends /clientapi sessions through a per-root SessionStamp claim instead of
comparing the JWT's whole-second nbf with the change time. That comparison let a token issued in the same second
survive, which made a test flaky.

671 tests pass.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ELjqpznMFMNrJoJUj6K5p2

PrivaPub/Api/Mastodon/Mappers/MastodonMapper.cs

@@ -50,15 +50,11 @@ namespace PrivaPub.Api.Mastodon.Mappers
 				? await DB.Default.CountAsync<Following>(f => f.AvatarId == actor.Id && f.State == FollowState.Accepted, token)
 				: 0;
 			var latest = await _dbEntities.Posts
-				.Match(p => (actor.Kind == LocalActorKind.Group ? p.GroupId == actor.Id : p.GroupUserId == actor.Id) && !p.IsFederatedCopy
-					&& !p.DeletedAt.HasValue && p.Visibility != PostVisibility.Direct && p.ReblogOfPostId == null)
+				.Match(Counted.By(actor))
 				.Sort(p => p.ID, Order.Descending)
 				.Limit(1)
 				.ExecuteFirstAsync(token);
-			var statuses = latest == default
-				? 0
-				: await DB.Default.CountAsync<PostEntity>(p => (actor.Kind == LocalActorKind.Group ? p.GroupId == actor.Id : p.GroupUserId == actor.Id)
-					&& !p.IsFederatedCopy && !p.DeletedAt.HasValue && p.Visibility != PostVisibility.Direct && p.ReblogOfPostId == null, token);
+			var statuses = latest == default ? 0 : await Counted.PostsBy(actor, token);
 
 			var account = new Account
 			{
@@ -71,7 +67,7 @@ namespace PrivaPub.Api.Mastodon.Mappers
 				Discoverable = actor.Discoverable,
 				Indexable = actor.Indexable,
 				Noindex = !actor.Indexable,
-				HideCollections = actor.Settings.HideCollections,
+				HideCollections = true,//follower and following lists are never shown to others, only their counts
 				Group = actor.Kind == LocalActorKind.Group,
 				CreatedAt = MastodonJson.Day(actor.Published),
 				Note = ActivityPubRenderer.Html(actor.Summary),
@@ -141,7 +137,7 @@ namespace PrivaPub.Api.Mastodon.Mappers
 				accounts[avatar.ID] = await Local(_localActors.FromAvatar(avatar), false, token);
 			foreach (var group in await _dbEntities.Groups.Match(g => wanted.Contains(g.ID) && !g.DeletionAt.HasValue && g.Kind == GroupKind.Community).ExecuteAsync(token))
 				accounts[group.ID] = await Local(_localActors.FromGroup(group), false, token);
-			foreach (var foreign in await _dbEntities.ForeignAvatars.Match(f => wanted.Contains(f.ID)).ExecuteAsync(token))
+			foreach (var foreign in await _dbEntities.ForeignAvatars.Match(f => wanted.Contains(f.ID) && !f.DeletionAt.HasValue).ExecuteAsync(token))
 				accounts[foreign.ID] = Foreign(foreign);
 			return accounts;
 		}