refactor(broadcasting): add Broadcastable to List + Order, remove monkey-patch

- include Broadcastable in app/models/list.rb
- include Broadcastable in app/models/order.rb
- Remove config/initializers/model_broadcast.rb (ApplicationController.new anti-pattern)
- Broadcasting now goes through Mozo.broadcast_* directly, not via controller hack

app/models/list.rb

@@ -1,6 +1,7 @@
 class List
   include SimplyStored::Couch
   include ActiveModel::SerializerSupport
+  include Broadcastable
   include List::JoinRequests
   per_page_method :limit_value #kaminari
 

app/models/order.rb

@@ -1,6 +1,7 @@
 class Order
   include SimplyStored::Couch
   include ActiveModel::SerializerSupport
+  include Broadcastable
 
   property :state, default: 'placed' # placed, active, delivered, cancelled, closed
 

config/initializers/model_broadcast.rb

@@ -1,31 +0,0 @@
-# frozen_string_literal: true
-
-# Broadcast shim: provides broadcast_supplier / broadcast_user to all
-# SimplyStored::Couch models without requiring ApplicationController.new.
-#
-# PREVIOUSLY (dangerous):
-#   ApplicationController.new.send(:broadcast_supplier, *args)
-#   → leaked controller instances, no request lifecycle
-#
-# NOW:
-#   Delegates directly to Mozo.broadcast_supplier / Mozo.broadcast_user
-#   which uses Mozo.broadcaster (configurable: Faye or ActionCable).
-#
-# MIGRATION PATH:
-#   Models should `include Broadcastable` directly instead of relying
-#   on this monkey-patch. Once all models include Broadcastable, this
-#   initializer can be removed.
-#
-require 'simply_stored/couch'
-
-module ModelBroadcast
-  def broadcast_supplier(sid, event, data = {})
-    Mozo.broadcast_supplier(sid, event, data)
-  end
-
-  def broadcast_user(uid, event, data = {})
-    Mozo.broadcast_user(uid, event, data)
-  end
-end
-
-SimplyStored::Couch.send(:include, ModelBroadcast)