feat: #3618242 Add the Translation Management Tool (TMGMT) and Drupal Canvas page translation to the Varbase Internationalization Base recipe

Issue: #3618242 Add the Translation Management Tool (TMGMT) and Drupal Canvas page translation to the Varbase Internationalization Base recipe

Supersedes #3588171 Canvas Multilingual (committed, then reverted, closed won't fix).

What changed

The recipe adds no module install. It makes Drupal Canvas pages translatable through Drupal Canvas's own multilingual support, and ships the Translation Management Tool in the codebase for sites that want it.

1. recipe.yml config actions enable content translation for the Drupal Canvas Page entity (language.content_settings.canvas_page.canvas_page) and make its component input values translatable (core.base_field_override.canvas_page.canvas_page.components, with translation_sync on inputs). These are the Drupal Canvas translation enablement: Drupal Canvas 1.10 handles page translation natively (symmetric translation), so no translation UI module is required for pages.
2. composer.json requires drupal/tmgmt: ~1 and adds the "Drupal Canvas" and "TMGMT" keywords. The Translation Management Tool is NOT enabled by the recipe; sites that want translation jobs, local translators or a provider enable it themselves (drush en tmgmt tmgmt_content tmgmt_config tmgmt_local).
3. recipe.yml install: is unchanged, and no permission grants were added.
4. README.md and CHANGELOG.md (Unreleased) document the addition.

Testing

Two fresh installs through the browser installer on a Varbase 11 DDEV site (Drupal 11.4.5, Drupal Canvas 1.10.1), Varbase Starter site template, recipe applied through the Project Browser UI.

Still applies to this scope:

• language, locale, config_translation, content_translation, eca, eca_language enabled by the recipe.
• Content translation enabled for canvas_page, with components translatable.
• The Translation Management Tool stayed off: 0 of 9 TMGMT modules enabled, all available in the codebase. Enabling them afterwards with drush worked.
• No HTTP 500 in the Drupal Canvas editor on the multilingual site.

No longer applies: the earlier verification ran the Drupal Canvas Translate workspace (/canvas/app/canvas_translate) with that module enabled manually. Drupal Canvas Translate is out of scope now, so that run is not evidence for this change. Page translation through Drupal Canvas's own multilingual support has not been re-verified end to end on this final scope.

Local pipeline green with gitlab-ci-local: build:composer-validate PASS, validate:yaml-lint PASS.

AI-Generated: Yes

Checkpoints:

• File an issue
• Addition/Change/Update/Fix
• Testing to ensure no regression
• Automated unit testing coverage
• Automated functional testing coverage
• UX/UI designer responsibilities
• Readability
• Accessibility
• Performance
• Security
• Developer Documentation
• User Guide Documentation
• Reviewed by human
• Code review by maintainers
• Full testing and approval
• Credit contributors
• Review with the product owner
• Release notes snippet
• Release