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  domain_count counts the servers we have exchanged with; which ones stays unpublished (peers is empty).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/Services/GroupUsersService.cs

@@ -210,6 +210,7 @@ namespace PrivaPub.Services
 					group.UpdatedAt = DateTime.UtcNow;
 					await DB.Default.SaveAsync(group, token);
 				}
+				await FollowAsMember(group, form.AvatarId, token);
 
 				result.Data = ToView(group, form.AvatarId);
 				return result;
@@ -221,6 +222,33 @@ namespace PrivaPub.Services
 			}
 		}
 
+		// Joining by invitation is following, as a local follow of the group would be: the member counts among its
+		// followers (so /groupies and /flock agree) and gets its posts in the home timeline.
+		async Task FollowAsMember(GroupEntity group, string avatarId, CancellationToken token)
+		{
+			var persona = await _localActors.FindById(LocalActorKind.Person, avatarId, token);
+			var target = _localActors.FromGroup(group);
+			if (persona == default)
+				return;
+			await DB.Default.Update<Follower>()
+				.Match(f => f.LocalActorId == group.ID && f.LocalActorKind == LocalActorKind.Group && f.ActorURI == persona.Uri)
+				.Modify(f => f.InboxURL, persona.Inbox)
+				.Modify(f => f.SharedInboxURL, persona.SharedInbox)
+				.Modify(f => f.IsAccepted, true)
+				.Modify(b => b.SetOnInsert(f => f.CreationDate, DateTime.UtcNow))
+				.Option(o => o.IsUpsert = true)
+				.ExecuteAsync(token);
+			await DB.Default.Update<Models.Social.Following>()
+				.Match(f => f.AvatarId == persona.Id && f.TargetActorURI == target.Uri)
+				.Modify(f => f.TargetAccountId, group.ID)
+				.Modify(f => f.TargetIsLocal, true)
+				.Modify(f => f.TargetInboxURL, target.Inbox)
+				.Modify(f => f.State, Models.Social.FollowState.Accepted)
+				.Modify(b => b.SetOnInsert(f => f.CreatedAt, DateTime.UtcNow))
+				.Option(o => o.IsUpsert = true)
+				.ExecuteAsync(token);
+		}
+
 		public async Task<WebResult> LeaveGroup(string rootUserId, GroupMembershipForm form, CancellationToken token)
 		{
 			var result = new WebResult();
@@ -238,6 +266,12 @@ namespace PrivaPub.Services
 				group.Members.RemoveAll(m => !m.IsForeign && m.AvatarId == form.AvatarId);
 				group.UpdatedAt = DateTime.UtcNow;
 				await DB.Default.SaveAsync(group, token);
+				// leaving is unfollowing, as joining was following
+				var groupUri = _localActors.FromGroup(group).Uri;
+				var personaUri = (await _localActors.FindById(LocalActorKind.Person, form.AvatarId, token))?.Uri;
+				await DB.Default.DeleteAsync<Models.Social.Following>(f => f.AvatarId == form.AvatarId && f.TargetActorURI == groupUri);
+				if (personaUri != default)
+					await DB.Default.DeleteAsync<Follower>(f => f.LocalActorId == group.ID && f.LocalActorKind == LocalActorKind.Group && f.ActorURI == personaUri);
 				return result;
 			}
 			catch (Exception ex)