Domain blocks: suspend, silence, reject media

DomainBlock (domain, severity, reject-media, public and private comment)
covers the domain and its subdomains. Admins manage them under
/clientapi/admin/domainblocks/{list,insert,delete}; the set is kept in
memory, reloaded on every change and at most five minutes stale.

A suspended domain is refused by FederationHttp.IsAllowed, so nothing is
fetched from it and no job delivers to it, and the inbox drops its
activities with a 202 before fetching any key. Reject-media strips the
attachments of posts from that domain. Silence is recorded for the
timelines and notifications that arrive in P1.2.

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

PrivaPub/Federation/Inbox/Handlers/CreateHandler.cs

@@ -2,6 +2,7 @@ using MongoDB.Driver;
 using MongoDB.Entities;
 
 using PrivaPub.Federation.Actors;
+using PrivaPub.Federation.Moderation;
 using PrivaPub.Federation.Objects;
 using PrivaPub.Federation.Outbox;
 using PrivaPub.Federation.Rendering;
@@ -26,13 +27,16 @@ namespace PrivaPub.Federation.Inbox.Handlers
 		readonly ILocalActorService _localActors;
 		readonly IRemoteActorService _remoteActors;
 		readonly IDeliveryService _delivery;
+		readonly IDomainBlocks _domainBlocks;
 
-		public CreateHandler(DbEntities dbEntities, ILocalActorService localActors, IRemoteActorService remoteActors, IDeliveryService delivery)
+		public CreateHandler(DbEntities dbEntities, ILocalActorService localActors, IRemoteActorService remoteActors, IDeliveryService delivery,
+			IDomainBlocks domainBlocks)
 		{
 			_dbEntities = dbEntities;
 			_localActors = localActors;
 			_remoteActors = remoteActors;
 			_delivery = delivery;
+			_domainBlocks = domainBlocks;
 		}
 
 		public string Type => "Create";
@@ -130,7 +134,7 @@ namespace PrivaPub.Federation.Inbox.Handlers
 				Language = note.Language,
 				Mentions = mentions,
 				Tags = note.Tags.ToList(),
-				Media = note.Attachments.ToList(),
+				Media = _domainBlocks.Find(new Uri(author.ActorURI).Host)?.RejectMedia == true ? new() : note.Attachments.ToList(),
 				InReplyToURI = note.InReplyTo,
 				AnsweringToPostId = parent?.ID,
 				InReplyToAccountId = parent?.AuthorAccountId ?? parent?.GroupUserId,