Incompatibility with Rails 7.2+ permanent_connection_checkout = :disallowed

In Rails 7.2+, using `ActiveRecord::Base.connection` directly is no longer necessary, and Rails can be configured to produce either a deprecation warning or an error for this code pattern. The behavior can be toggled via `config.active_record.permanent_connection_checkout`. While the default setting (true) doesn't cause any issues, setting it to `:disallowed` produces errors when using this gem.

See:
https://guides.rubyonrails.org/configuring.html#config-active-record-permanent-connection-checkout
https://prateekcodes.com/rails-with-connection-better-database-connection-management/

Start by locating the gem's use of ActiveRecord::Base.connection, then reproduce the issue in Rails 7.2+ with config.active_record.permanent_connection_checkout set to :disallowed. Done means the gem's advisory-lock behavior works without the Rails connection-checkout error under that configuration.

Written by the indexing model from the issue text.