Add support for federating `memorial` attribute (#26583)

app/helpers/context_helper.rb

@@ -21,6 +21,7 @@ module ContextHelper
     blurhash: { 'toot' => 'http://joinmastodon.org/ns#', 'blurhash' => 'toot:blurhash' },
     discoverable: { 'toot' => 'http://joinmastodon.org/ns#', 'discoverable' => 'toot:discoverable' },
     indexable: { 'toot' => 'http://joinmastodon.org/ns#', 'indexable' => 'toot:indexable' },
+    memorial: { 'toot' => 'http://joinmastodon.org/ns#', 'memorial' => 'toot:memorial' },
     voters_count: { 'toot' => 'http://joinmastodon.org/ns#', 'votersCount' => 'toot:votersCount' },
     olm: {
       'toot' => 'http://joinmastodon.org/ns#', 'Device' => 'toot:Device', 'Ed25519Signature' => 'toot:Ed25519Signature', 'Ed25519Key' => 'toot:Ed25519Key', 'Curve25519Key' => 'toot:Curve25519Key', 'EncryptedMessage' => 'toot:EncryptedMessage', 'publicKeyBase64' => 'toot:publicKeyBase64', 'deviceId' => 'toot:deviceId',

app/serializers/activitypub/actor_serializer.rb

@@ -7,13 +7,14 @@ class ActivityPub::ActorSerializer < ActivityPub::Serializer
   context :security
 
   context_extensions :manually_approves_followers, :featured, :also_known_as,
-                     :moved_to, :property_value, :discoverable, :olm, :suspended
+                     :moved_to, :property_value, :discoverable, :olm, :suspended,
+                     :memorial
 
   attributes :id, :type, :following, :followers,
              :inbox, :outbox, :featured, :featured_tags,
              :preferred_username, :name, :summary,
              :url, :manually_approves_followers,
-             :discoverable, :published
+             :discoverable, :published, :memorial
 
   has_one :public_key, serializer: ActivityPub::PublicKeySerializer
 

app/services/activitypub/process_account_service.rb

@@ -116,6 +116,7 @@ class ActivityPub::ProcessAccountService < BaseService
     @account.also_known_as           = as_array(@json['alsoKnownAs'] || []).map { |item| value_or_id(item) }
     @account.discoverable            = @json['discoverable'] || false
     @account.indexable               = @json['indexable'] || false
+    @account.memorial                = @json['memorial'] || false
   end
 
   def set_fetchable_key!