Home timelines, mention notifications, and threads that fetch their parents

Fanout writes a TimelineEntry for every persona a post should reach: the
author, local followers of a local author, local followers of a remote one,
the members of a direct conversation or a circle. Mastodon's home rules
apply when it is written: a reply shows only to followers of both sides
(or to the one replied to), a reblog only where reblogs are wanted. A
mention of a local persona becomes a Mention notification.

Inbound posts are now also kept when a persona follows their author.

RemotePosts holds what CreateHandler and backfill share: building a Post
from a note, and fetching a public parent the first time a reply to it
arrives, so its author is known (a reply to an unknown or non-public
parent stays out of home timelines). Each fetched ancestor queues a
FetchAncestors job for the next one, up to ten deep.

/clientapi/timeline/home and /clientapi/notifications (with
/notifications/read) page by max_id for the persona's own root only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB

PrivaPub/Middleware/SocialPubConfigurations.cs

@@ -18,6 +18,7 @@ using PrivaPub.Federation.Moderation;
 using PrivaPub.Federation.Inbox.Handlers;
 using PrivaPub.Domain.Content;
 using PrivaPub.Domain.Social;
+using PrivaPub.Domain.Timelines;
 using PrivaPub.Infrastructure.Http;
 using PrivaPub.Infrastructure.Jobs;
 using Microsoft.Extensions.Options;
@@ -58,6 +59,7 @@ namespace PrivaPub.Middleware
 				.AddSingleton<IRemoteActorService, RemoteActorService>()
 				.AddSingleton<IDeliveryService, DeliveryService>()
 				.AddSingleton<IOutboxPublisher, OutboxPublisher>()
+				.AddSingleton<IFanout, Fanout>()
 				.AddSingleton<IInboxReceiver, InboxReceiver>()
 				.AddSingleton<IActivityHandler, FollowHandler>()
 				.AddSingleton<IActivityHandler, AcceptHandler>()
@@ -67,6 +69,8 @@ namespace PrivaPub.Middleware
 				.AddSingleton<IActivityHandler, DeleteHandler>()
 				.AddSingleton<IActivityHandler, UpdateHandler>()
 				.AddSingleton<IJobHandler, InboxProcessor>()
+				.AddSingleton<IRemotePosts, RemotePosts>()
+				.AddSingleton<IJobHandler, AncestorsJobHandler>()
 				.AddSingleton<IJobQueue, JobQueue>()
 				.AddSingleton<IHostCircuitBreaker, HostCircuitBreaker>()
 				.AddSingleton<IJobHandler, DeliveryJobHandler>()
@@ -123,6 +127,7 @@ namespace PrivaPub.Middleware
 				.AddTransient<IGroupUsersService, GroupUsersService>()
 				.AddTransient<IPostsService, PostsService>()
 				.AddTransient<IFollowService, FollowService>()
+				.AddTransient<ITimelineService, TimelineService>()
 				.AddSingleton<AppConfigurationService>()
 				.AddHttpContextAccessor()
 				.AddMemoryCache()