Changed the BIMI authentication result displayed in the Thunderbird message header area to show only the authentication status: **PASS**, **FAIL**, or **N/A**.

Detailed BIMI authentication information, including the evaluated domain and failure reasons, remains available in the add-on popup.

This change only affects the user interface. The BIMI validation and authentication logic has not been changed.

Added localization support.

This version adds multilingual support using the standard WebExtension `_locales` mechanism. The add-on now supports English and Japanese UI text, with English set as the default locale.

Also improved the popup text handling so that labels, status messages, and BIMI check result reasons can be displayed according to the user’s language environment.