Rename or replace `actionAction()` with an explicit apply-action API

[javihgil]

Problem

The configuration entry point for the apply flow is currently named actionAction(), while it actually processes ApplyActionConfiguration.

Current behavior

• Configuration::actionAction() contains TODO comments saying it should probably be apply action.
• The helper is used for the apply flow in the controller.
• processAction() also receives an $action argument that is not used.

Why it matters

The current naming makes the public configuration API harder to understand and suggests unfinished design in one of the main action types of the package.

Suggested direction

Expose a clear apply-named configuration entry point, keep backward compatibility if needed, and remove unused API leftovers once the transition is defined.