[Fix] Task memory history banner keeps returning after ingestion

[roomote-roomote]

​Opened on behalf of @mrubens. Follow up by mentioning @roomote-roomote or in the web UI.

What changed

• enqueue task-memory outbox rows atomically from every completed-run path, including snapshot success, standby retention, non-resumable shutdown, and snapshot-failure recovery
• recognize file-backed Brain gateway tokens when deciding whether completion should enqueue a memory
• split event-less completed runs at the durable one-time backfill checkpoint, keeping genuine history in the existing banner and reporting post-checkpoint gaps as an operational warning with a repair action
• describe queue timestamps as processed rather than recorded, since deliberately skipped events also advance them
• add regression coverage for activation, persistence, completion orchestration, count classification, and dashboard rendering, and update the Brain documentation

Why this change was made

The history banner counted every completed run without an outbox row as pre-Brain history. File-backed deployments and several direct BullMQ completion paths could omit that row for newly completed runs, so the banner repeatedly returned with recent tasks even after backfill.

Impact

Recent completed tasks now durably enter the normal memory queue in the same transaction as completion. The historical ingestion banner remains a one-time backfill signal, while any future post-checkpoint recording gap is labeled accurately and can be repaired without conflating it with old history.

Targeted task-memory tests, package type checks, repository lint, pre-push checks, and docs validation pass. Browser screenshots are not attached because the local Brain fixture required unavailable Docker and the remaining authenticated route was onboarding-guarded.

[roomote-community]

No new code issues found. See task

_{Reviewed bd0d076}