Enable Tugboat live previews

Add Tugboat configuration to enable live preview environments for merge requests.

Steps

1. Create .tugboat/config.yml.
2. Enable Tugboat integration on the project's GitLab settings.
3. The preview environment should:
   • Use tugboatqa/drupal:11 and tugboatqa/mariadb images
   • Install the module via Composer path repository
   • Enable webform_workflows_element and its dependencies (workflows, webform)
   • Optionally enable submodules (webform_workflows_element_views, webform_workflows_element_maestro) if their dependencies are available

Proposed .tugboat/config.yml

services:
  php:
    image: tugboatqa/drupal:11
    default: true
    http: false
    depends: mysql
    commands:
      update: |
        set -eux
        cd $DRUPAL_COMPOSER_ROOT
        composer config minimum-stability dev
        composer config repositories.tugboat path $TUGBOAT_ROOT
        composer require drupal/webform_workflows_element
        vendor/bin/drush \
          --yes \
          --db-url=mysql://tugboat:tugboat@mysql:3306/tugboat \
          --site-name="Live preview for ${TUGBOAT_PREVIEW_NAME}" \
          --account-pass=admin \
          site:install standard
        echo "\$settings['trusted_host_patterns'] = ['\.tugboatqa\.com\$'];" >> $DOCROOT/sites/default/settings.php
        mkdir -p $DRUPAL_DOCROOT/sites/default/files
        chgrp -R www-data $DRUPAL_DOCROOT/sites/default/files
        chmod 2775 $DRUPAL_DOCROOT/sites/default/files
        chmod -R g+w $DRUPAL_DOCROOT/sites/default/files
        vendor/bin/drush --yes pm:enable webform_workflows_element
      build: |
        set -eux
        cd $DRUPAL_COMPOSER_ROOT
        composer install --optimize-autoloader
        composer update drupal/webform_workflows_element --with-all-dependencies
        vendor/bin/drush --yes updb
        vendor/bin/drush cache:rebuild
  mysql:
    image: tugboatqa/mariadb