Contribution Submit (worker skill)

Creates or updates the merge request and prepares the required AI disclosure.

Backs /drupal-ai-contrib:submit. Load the knowledge layer via dev-guides-navigator: drupal/contributing-with-ai/merge-request-workflow, drupal/contributing/issue-forks-merge-requests, drupal/contributing-with-ai/commit-messages, drupal/contributing-with-ai/disclosure-checkboxes, drupal/contributing/contribution-etiquette-rtbc-credit.