[Fix] Session notifications can be lost during delivery

[roomote-roomote]

​Opened on behalf of @daniel-lxs. Follow up by mentioning @roomote-roomote, in the web UI, or in Slack.

What changed

• Route PR feedback, PR conflict, PR terminal-status, and artifact publication notifications directly through the durable Fast parent-event inbox.
• Treat successful durable admission as the handoff boundary instead of waiting for presentation completion.
• Remove the polling helper and legacy task/conversation delivery claims so the queue event key is the single notification idempotency boundary.
• Preserve review-pipeline suppression from PR feat: attach automatic PR reviews to the Fast session that opened the PR #2150 and keep lifecycle logging best-effort after admission.
• Honor settled and active pre-migration artifact markers during rolling deployments without creating new legacy claims.

Why this change was made

Ambient Session notifications need durable ordering and recovery, but their producers do not need to block while the parent Session presents them. Using the established enqueue-only pattern avoids polling latency and competing idempotency claims while retaining retries for genuine admission failures.

Impact

Notification producers return as soon as PostgreSQL accepts the durable event. Queue recovery remains responsible for eventual presentation, repeated admissions collapse on the stable event key, and artifact confirmation retries only when durable admission fails or a previous-release presentation claim is still active.

[roomote-community]

No new code issues found. See task

• Preserve the existing artifact-delivery marker during the durable-admission migration so upload replays cannot double-post prior deliveries.

_{Reviewed b91a511}

[roomote-roomote]

Fixed every current Test failure. Latest develop is merged, suppression fixtures now model the TaskRun.payloadKind contract used by isPrReviewRun, and the rolling-deployment artifact marker bridge remains covered. Local CI-mode SDK passed all 1,454 tests; GitHub Test and every required check are now green. See task · Commit