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  domain_count counts the servers we have exchanged with; which ones stays unpublished (peers is empty).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

@@ -41,7 +41,9 @@ namespace PrivaPub.Tests.Http
 			var v2 = (await anonymous.Get("/api/v2/instance")).Ok();
 			Assert.Equal(InstanceController.Version, v2.Body.Text("version"));
 			Assert.Equal(PrivaPubHost.Host, v2.Body.Text("domain"));
-			Assert.Equal($"wss://{PrivaPubHost.Host}", v2.Body["configuration"]!["urls"].Text("streaming"));
+			Assert.Null(v2.Body["configuration"]!["urls"]!["streaming"]);//nothing streams yet, so nothing is advertised
+			Assert.Equal(PrivaPub.Api.Mastodon.Controllers.StatusesController.MaxPins, v2.Body["configuration"]!["accounts"].Number("max_pinned_statuses"));
+			Assert.Contains("image/avif", v2.Body["configuration"]!["media_attachments"]!["supported_mime_types"]!.AsArray().Select(t => t!.GetValue<string>()));
 			Assert.True(v2.Body["registrations"].Flag("enabled"));
 			Assert.True((await anonymous.Get("/nodeinfo/2.1")).Ok().Body.Flag("openRegistrations"));
 			Assert.False(v2.Body["configuration"]!["translation"].Flag("enabled"));