feat: don't allow more documents than permitted

enterprise/app/controllers/api/v1/accounts/captain/documents_controller.rb

@@ -3,6 +3,7 @@ class Api::V1::Accounts::Captain::DocumentsController < Api::V1::Accounts::BaseC
   before_action -> { check_authorization(Captain::Assistant) }
 
   before_action :set_current_page, only: [:index]
+  before_action :ensure_within_plan_limit, only: [:create]
   before_action :set_documents, except: [:create]
   before_action :set_document, only: [:show, :destroy]
   before_action :set_assistant, only: [:create]
@@ -48,6 +49,10 @@ class Api::V1::Accounts::Captain::DocumentsController < Api::V1::Accounts::BaseC
     @current_page = permitted_params[:page] || 1
   end
 
+  def ensure_within_plan_limit
+    Current.account.account.usage_limits[:captain][:documents][:current_available].positive?
+  end
+
   def permitted_params
     params.permit(:assistant_id, :page, :id, :account_id)
   end