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.Tests/Support/Peer.cs

@@ -6,7 +6,9 @@ using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.Options;
 
+using PrivaPub.Federation.Moderation;
 using PrivaPub.Infrastructure.Http;
+using PrivaPub.Models.Federation;
 
 using System.Collections.Concurrent;
 
@@ -63,7 +65,7 @@ namespace PrivaPub.Tests.Support
 
 		public void Answer(string path, int status, TimeSpan delay = default) => _answers[path] = (status, delay);
 
-		public static FederationHttp Http(IMemoryCache cache = default)
+		public static FederationHttp Http(IMemoryCache cache = default, IDomainBlocks blocks = default)
 		{
 			var options = new FederationOptions { AllowPrivateNetworks = true, AllowPlainHttp = true };
 			var services = new ServiceCollection();
@@ -71,12 +73,19 @@ namespace PrivaPub.Tests.Support
 				.ConfigurePrimaryHttpMessageHandler(() => SafeHttpHandlerFactory.Create(options));
 			return new FederationHttp(services.BuildServiceProvider().GetRequiredService<IHttpClientFactory>(),
 				cache ?? new MemoryCache(new MemoryCacheOptions()), new StaticOptions<FederationOptions>(options),
-				NullLogger<FederationHttp>.Instance);
+				blocks ?? new NoBlocks(), NullLogger<FederationHttp>.Instance);
 		}
 
 		public async ValueTask DisposeAsync() => await _app.DisposeAsync();
 	}
 
+	public sealed class NoBlocks : IDomainBlocks
+	{
+		public DomainBlock Find(string host) => default;
+		public bool IsSuspended(string host) => false;
+		public Task Reload(CancellationToken token) => Task.CompletedTask;
+	}
+
 	public sealed record HttpRequestRecord(string Method, string Path, string Signature);
 
 	public sealed class StaticOptions<T> : IOptionsMonitor<T>