rubocop fixes

Author: rsmithlal

app/models/concerns/better_together/tracked_activity.rb

@@ -10,7 +10,9 @@ module TrackedActivity
       include PublicActivity::Model
 
       tracked owner: proc { |controller, _model| controller&.helpers&.current_person },
+              # rubocop:todo Lint/UnderscorePrefixedVariableName
               privacy: proc { |_controller, _model| _model.privacy if _model.respond_to?(:privacy) }
+      # rubocop:enable Lint/UnderscorePrefixedVariableName
 
       has_many :activities, as: :trackable, class_name: 'PublicActivity::Activity', dependent: :destroy
     end

db/migrate/20250703214031_add_default_activity_parameters.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddDefaultActivityParameters < ActiveRecord::Migration[7.1]
+class AddDefaultActivityParameters < ActiveRecord::Migration[7.1] # rubocop:todo Style/Documentation
   def change
     change_column_default :better_together_activities, :parameters, from: nil, to: '{}'
   end

db/migrate/20250703215419_add_privacy_to_activities.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class AddPrivacyToActivities < ActiveRecord::Migration[7.1]
+class AddPrivacyToActivities < ActiveRecord::Migration[7.1] # rubocop:todo Style/Documentation
   def change
     change_table :better_together_activities, &:bt_privacy
   end