test: #3633124 Add functional tests for Varbase AI Safety

Issue: https://www.drupal.org/i/3633124

Adds the Varbase functional testing suite (@vardot/varbase-e2e) and a varbase-e2e-test job: a fresh Varbase 11 site, the recipe applied twice, 12 scenarios, no AI key.

• CI checks the apply stops without a default model, then uses the AI module test provider (EchoAI) and installs ImageMagick.
• 1 @ai-provider scenario(s) run in their own job only when OPENAI_API_KEY is set.

Scenarios (13):

01-01-ai-safety-stack.feature

• Check the prompt safety and PII guardrail sets are there
• Check the guardrails cover script injection, medical advice and email addresses
• Check AI requests are logged and kept for 90 days
• Check the AI log and the observability settings open
• Check the image safety rule is on the Image media type

01-02-ai-safety-image-upload.feature

• Verify an image the vision model does not approve is refused with the safety message
• Verify a safe image is accepted (@ai-provider)

01-03-ai-safety-log.feature

• Check the image check from the upload was written to the AI log

01-04-ai-safety-access.feature

• Check the "Content editor" user cannot open the guardrails or the AI log
• Check the "Content admin" user cannot open the guardrails or the AI log
• Check the "SEO admin" user cannot open the guardrails or the AI log
• Check the "Site admin" user cannot open the guardrails or the AI log
• Check an anonymous visitor cannot read the AI log

Green locally with gitlab-ci-local: 12 passed.

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

🤖 Generated with Claude Code