Prompt

I’m refactoring nationality ,  add/edit form so it follows the same shell as the Line of Business module. Please walk me through converting it: create a build{Module}Schema function (along with its shared fieldsNames) under a config folder, make the component extend FormBuilderAddEditBaseComponent, inject services via inject(), and wire up toggleable mode (add/edit) through signals/computed state. Also outline how to register any option providers needed in the feature module, explain how to reuse FormContext stores for files/options if the form uses them, and describe how action handling (submit, cancel) and message keys should be derived so every module ends up with the same architecture.