Add following_url to accounts (#36093)

app/models/account.rb

@@ -31,6 +31,7 @@
 #  outbox_url                    :string           default(""), not null
 #  shared_inbox_url              :string           default(""), not null
 #  followers_url                 :string           default(""), not null
+#  following_url                 :string           default(""), not null
 #  protocol                      :integer          default("ostatus"), not null
 #  memorial                      :boolean          default(FALSE), not null
 #  moved_to_account_id           :bigint(8)
@@ -123,6 +124,7 @@ class Account < ApplicationRecord
   validates_with EmptyProfileFieldNamesValidator, if: -> { local? && will_save_change_to_fields? }
   with_options on: :create, if: :local? do
     validates :followers_url, absence: true
+    validates :following_url, absence: true
     validates :inbox_url, absence: true
     validates :shared_inbox_url, absence: true
     validates :uri, absence: true

app/services/activitypub/process_account_service.rb

@@ -102,6 +102,7 @@ class ActivityPub::ProcessAccountService < BaseService
     @account.outbox_url              = valid_collection_uri(@json['outbox'])
     @account.shared_inbox_url        = valid_collection_uri(@json['endpoints'].is_a?(Hash) ? @json['endpoints']['sharedInbox'] : @json['sharedInbox'])
     @account.followers_url           = valid_collection_uri(@json['followers'])
+    @account.following_url           = valid_collection_uri(@json['following'])
     @account.url                     = url || @uri
     @account.uri                     = @uri
     @account.actor_type              = actor_type

db/migrate/20250912082651_add_following_url_to_accounts.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddFollowingURLToAccounts < ActiveRecord::Migration[8.0]
+  def change
+    add_column :accounts, :following_url, :string, default: '', null: false
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2025_09_11_163952) do
+ActiveRecord::Schema[8.0].define(version: 2025_09_12_082651) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_catalog.plpgsql"
 
@@ -198,6 +198,7 @@ ActiveRecord::Schema[8.0].define(version: 2025_09_11_163952) do
     t.datetime "requested_review_at", precision: nil
     t.boolean "indexable", default: false, null: false
     t.string "attribution_domains", default: [], array: true
+    t.string "following_url", default: "", null: false
     t.index "(((setweight(to_tsvector('simple'::regconfig, (display_name)::text), 'A'::\"char\") || setweight(to_tsvector('simple'::regconfig, (username)::text), 'B'::\"char\")) || setweight(to_tsvector('simple'::regconfig, (COALESCE(domain, ''::character varying))::text), 'C'::\"char\")))", name: "search_index", using: :gin
     t.index "lower((username)::text), COALESCE(lower((domain)::text), ''::text)", name: "index_accounts_on_username_and_domain_lower", unique: true
     t.index ["domain", "id"], name: "index_accounts_on_domain_and_id"