- Fix webhook translation import: read project id, file id and target language
  from the actual Crowdin payload, with a backward-compatible fallback to the
  flat keys; guard against unknown job/job item.
- Fix WEBXML export: correct plugin constructor signature (was breaking export),
  make XML element names safe for non-Latin labels, drop deprecated reset() on
  SimpleXMLElement.
- Fix PHP deprecations in createWebhook() (unserialize(NULL) / writing to a boolean).