Review gate — wave-5 suite passed (task review-wave-5): the suite stands as the compatibility instrument and the engine specs flip to stable. All 25 mechanism rows per engine column read in full and verified against core-contract.md §Verification backlog item by item (the appendix map's every claim confirmed by the pinning row/text, incl. the combined-coverage claim for save_offset_tx exactly-once and the five engine-side pins — SQLite open row, watcher-cadence knob, M-1 sweep-rollback: SQLite trigger seam live + the pg frame's in_tx structure code-read; beyond-64 skip-forward; cap-curve); all 25 'Contract stamp:' markers checked against the cited ADR § bodies (ADR-008 §3/§5/§7/§8, 009 §1/§3/§4/§6, 010 §1-§5, 014 §1, 015 §1-§5, 016 §5, 020 §1-§4, 021 §1/§3/§4/§5, 023 §1/§2, 012 §2, 019, 007, 006) — the enqueue_opts_resolution amendment accumulation rides ADR-023 §2 per the convention; all six parked dispositions audited and recorded (M-1 engine-side, skip-forward engine-side twins, cap engine-side, fire-wake parity not demanded, lock busy-path no divergence, reconnect-success test taken); conformance spot-checks clean (no row pins beyond ADR text, determinism posture holds incl. the two documented extensions, cross-references not duplication). Green on both engines this session: workspace build/test/clippy -D warnings/fmt; SQLite column 25/25 server-less twice (isolated + concurrent); pg column 25/25 vs the harness server three full runs (two consecutive + one concurrent with the SQLite column) plus 6 focused --test-threads=6 stress runs of the two development-time flake rows — all clean, the two unreproducible pg failures recorded with the bounded investigation and a wave-6 watch flag in the task's Notes. Docs: engine-sqlite.md and engine-postgres.md frontmatter status draft → stable with dated annotations citing this gate; implementation.md wave-table row 5 and review-rounds entry; suite-opts-backoff-rows.md placeholder remnants removed. Wave 6 (release readiness) decomposition may proceed

docs/architecture/engine-postgres.md

@@ -1,6 +1,6 @@
 ---
-status: draft
-last_updated: 2026-10-07 (ADR-021 — third review round: tx reads, claimed_at, schedule queue validation, drop=rollback, receiver arms)
+status: stable
+last_updated: 2026-10-10 (review-wave-5 gate: the verification backlog fully discharged in the version-stamped contract suite, green against this engine; spec flipped draft → stable)
 ---
 
 # Postgres engine