fix: project description editor never loads, blocking project save (#11302)

[BenJule]

Summary

Closes #11302. In the Project tab, the Description field is required but there's no editor to type into, and saving fails with "The project description is empty" with no way to fix it (see the screenshots in the issue).

Root cause

The description editors (CKEditor) are created in resources/web/model_new/js/ckeditor_config.js, but only inside the onload handler of a dynamically-loaded translation file:

script.src = `../include/ckeditor5/translations/${editorLanguage}.umd.js`;
script.onload = () => { ClassicEditor.create('#editor', ...); ... };

editor.html is navigated to without a ?lang= query, so editorLanguage falls back to navigator.language, which the webview commonly reports as en-US. That resolves to translations/en-us.umd.js, which doesn't exist (only en, en-au, en-gb ship). A missing file fires onerror, not onload, so the editors are never created: no description field appears, and the required-field validation then blocks saving for everyone in this situation, regardless of UI language.

Fix

Initialise the editors on both onload and onerror (guarded so they're created only once). If the translation file fails to load, the editors still come up (in English) instead of leaving the page with no description editor at all.

Test plan

• JS-only change in ckeditor_config.js, syntax-checked with node --check.
• Open the Project tab → Edit: the description editor now appears and a project can be saved, even when the resolved locale has no CKEditor translation file. When the translation does load, behaviour is unchanged (the guard prevents double init).