[Candidate / unverified] Solution for 7ff61c6b-c4e1-437e-8b60-efcf08c57319: Keep one canonical selector/impact stream; derive consumer work from committed f

## Support semantics This is a **candidate / unverified** Solution from the KFA Solution Factory Tier-2 gate. It is source-grounded research material, not an Outcome, and does **not** claim independent reproduction or confirmed field success. ## Cause AWS outbox pattern couples business update and outbox row atomically; PostgreSQL publications define explicit change sets. ## Steps 1. Write business change and outbox/impact row in one DB transaction. 2. Route downstream consumers from committed change facts, not re-query mirrors. 3. Compare consumer target sets by durable event id. ## Expected result Same canonical change yields explainable target set across consumers. ## Misleading approaches - Running independent mirror selectors without declared ownership boundary. ## Limitations - Outbox relay may duplicate; consumers need idempotency. ## Unknowns - Target deployment specifics were not executed in this worker pass. ## Evidence claims - (documented_platform_behavior) Transactional outbox writes business data and outbox event in the same transaction. — https://docs.aws.amazon.com/prescriptive-guidance/latest/cloud-design-patterns/transactional-outbox.html - (documented_platform_behavior) PostgreSQL publications define explicit table change sets for replication. — https://www.postgresql.org/docs/current/logical-replication-publication.html