Third review round follow-through: enqueue_tx stamp source, sweep_expired handle form, with_tx signature, and B-block ambiguity pins

docs/architecture/decisions/020-enqueue-opt-semantics-and-bridges.md

@@ -105,6 +105,17 @@ parities: 300 s / 3 / 5 s / none), not a handle's opts and not
 - **`ScheduleOpts` field growth post-release is class 3** (opts
   struct, [ADR-017](017-contract-versioning.md) §3's exemption) —
   stated so the pricing is visible now.
+- *(Annotated 2026-10-07, third review round follow-through: §3a's
+  "resolved over the queue handle's `QueueOpts`" reading applies only
+  to the auto-commit `Queue::enqueue` — the one call shape with a
+  queue handle in scope. Plain
+  `enqueue_tx(queue_name, opts, payload)` is a no-handle-open shape
+  too (a `TxHandle` never carries queue opts), so it stamps the
+  engine's plain-queue defaults (300 s / 3 / 5 s / none) exactly as
+  boundary fires do; the outbox's `outbox_enqueue_tx` keeps its
+  60 s/5/5 derived set ([ADR-014](014-outbox-tx-enqueue.md) §1).
+  Without this note the SQLite and pg implementers could legitimately
+  diverge on the tx path's stamp source.)*
 
 ### 4. The payload encoding: serde_json serialization of the trait `Value`, byte-exactly