Important: #99490 - Provide tag to add JavaScript Modules to importmap in Backend Form

See forge#99490

Description

The JavaScript module import map is static and only generated and loaded in the first request to a document. All possible future modules requested in later Ajax calls need to be registered already in the first initial request.

We are adding a new tag 'backend.form' that is used to identify JavaScript modules that can be used within the backend forms. This will ensure that the import maps are available for these modules even if the element is not displayed directly.

A typical use case for this is an InlineRelationRecord where the CKEditor is not part of the main record but needs to be loaded for the child record.

Example Configuration/JavaScriptModules.php

<?php

return [
    'dependencies' => [
        'backend',
    ],
    'tags' => [
        'backend.form',
    ],
    'imports' => [
        '@typo3/rte-ckeditor/' => 'EXT:rte_ckeditor/Resources/Public/JavaScript/',
        '@typo3/ckeditor5-bundle.js' => 'EXT:rte_ckeditor/Resources/Public/Contrib/ckeditor5-bundle.js',
    ],
];