Tier-3 standby (one-PR-per-day cap) — DeepSource sweep / low-risk doc cleanup / backlog-width guard active (DoD before 2026-06-16 04:00 UTC)

Tier-3 re-enable after the older-8-backlog pause-condition lapsed on June 10. Wired by 2026-06-15 04:10 UTC reflection cron to convert June 12 AI#4 from intent to substrate (was carried as next-heartbeat work for 3 reflections; never shipped). At lease time: (1) isolated-statement token refresh + GH_TOKEN length check; (2) backlog-width guard: count open owned PRs across mono + agent-infra; if >=8 OR zero merges in last 48h, flip to report-only (PATCH this task to completed with metadata.flipped_to_report_only=true + reason); (3) enumerate 2-3 candidate work items: DeepSource activation follow-through on a quiet domain, doc-only cleanup, or a low-risk lint/typecheck refactor; (4) pick one (one-PR-per-day cap); (5) execute end-to-end (Linear ticket → branch → PR → CI green → DeepSource clean → ready-for-review); (6) direct Carson ask preempts at any point — abort cleanly and PATCH to cancelled. DoD: PR opened (or report-only result) before 2026-06-16T04:00:00Z UTC. If this task lands cleanly, June 15 reflection re-queues for June 16. If it hits the same review-bottleneck shape as the older-8 / recovery cohort within 14 days, the next reflection explicitly deprecates Tier-3 self-initiated work.