Lark QA follow-up: correlate one in-window blocked DM with checked receiver rejection #1250

Parent

Part of #1019; qualification follow-up from completed source tracer #1040. Provider qualification coordination remains in #48.

Observed gap

R4 sent BH1040-R4-BLOCKED inside the authorized QA window at Human-reported 04:56 JST on 2026-10-09. The Human saw no reply/reaction, canonical inspection found no matching Source Event and no new Outbox/feedback, and the official log showed one successful receive event at 04:56:44.857. That log exposes neither message ID nor body, so the event is not independently correlated to the exact blocked marker. Absence alone does not prove a delivered message was rejected.

Existing automated coverage already verifies that the policy owner denies Admission and feedback for a blocked conversation. This issue adds precise live delivery evidence; it does not imply the implemented policy is known broken.

Narrow outcome

• Correlate one uniquely marked blocked DM with its exact platform message/event identity and evidence of arrival at the intended checked receiver, using existing supported surfaces or bounded sanitized process diagnostics.
• Show the existing policy rejects that conversation without a new Admission, Outbox, receipt/answer feedback or replay. Retain the owning command/revision and bounded timestamps; do not introduce another content store or consumer.
• Distinguish actual rejection from a message that never reached QA. Preserve R3's late marker and R4's minute-only correlation as historical evidence, without upgrading them to a pass.
• If a production-app window is required, obtain fresh specific Human authorization, arm cutoff/independent restore first, clean up and verify both production Lark/Discord replies afterward. Do not add app permissions implicitly.
• Update the bilingual QA status and IM identities and messaging: provider coordination #48 qualification record with the exact paired sources and honest result. Closing this single follow-up does not automatically qualify every unexercised runbook case or promote/publish a Provider pin.

Evidence

• Merged implementation feat(messaging): source-bound Lark receipt and answer feedback #1207 and evidence docs: record guarded Lark feedback qualification #1236.
• R4 sanitized facts.
• Candidate QA runbook.

No new production window is authorized by creating this issue. This evidence follow-up is separate from the completed feedback tracer and does not block starting the sibling Discord/Slack feedback implementations.