[19.0] queue_job_batch: migrate + tests

[tishmen]

Scope

• queue_job_batch, test_queue_job_batch

Depends

• Base PR: [19.0] queue_job: migrate + tests #834

Summary

• Migrate to 19.0; no functional changes beyond compatibility.

Pre-commit

• Ran; committed auto-fixes where needed.

Tests

• Local isolated runs could not load test_queue_job_batch (dependency resolution for test addons when split); validated install paths and syntax.
• CI will run the full suite once queue_job PR is merged.

[tishmen]

Closing as requested; will re-open after adjustments.