[asselstine]

Summary

• Drain lifecycle delivery batches before evaluating idle triggers.
• Block idle eligibility in SQL while a watched source completion has an eligible, unacknowledged lifecycle delivery.
• Preserve retry and deduplication behavior; queue-full deliveries are acknowledged and permit idle triggers after existing watched runs finish.
• Add PostgreSQL regressions for delayed ordering, a 101-delivery backlog, and queue-full handling.

Closes GEN-2752

Validation

• npm test (Node 24.12.0; PostgreSQL and Chromium prerequisites installed)

[linear]

GEN-2752