fix(notifications): resolve agent-push dispatch review findings from #4627

[iscekic]

Follow-up to #4627 addressing the two unresolved review comments from @jeanduplessis on NotificationChannelDO. Both were flagged but non-blocking, so #4627 merged approved; this PR resolves them. The agent-notification push path is still dark in production (its CLI companion Kilo-Org/kilocode#12392 is unapproved), so this lands ahead of the feature going live.

1. Concurrent-replay double-send (correctness)

Concurrent replays can send the same agent notification more than once. This writes pending before token lookup and Expo submission, but a request that observes pending is treated as immediately retryable…

The DO serializes turns, but a turn yields the isolate on every external await (presence RPC, Expo send). A replay of the same idempotency key can interleave while the first attempt is mid-flight, read the pending marker the first attempt left, treat it as a reusable retry slot, and submit a second OS push.

Fix: an in-memory in-flight claim (Set<string> keyed by idempotency key). A concurrent replay seeing a live claim returns duplicate; a sequential post-failure retry (claim already released) still reuses the storage pending slot exactly as before. New test drives two concurrent dispatches of the same key with a held-open Expo send and asserts exactly one submission.

2. PII in push-sink logs (privacy)

Push-sink mode logs the complete notification title, agent/user-controlled body, and data object… allows sensitive session content… to be retained in local, CI, or aggregated Worker logs.

The dev/E2E-only sink (PUSH_SINK_MODE=log) logged full title/body/data.

Fix: log content-free metadata only — sizes, data key names, and the fixed type discriminator. The sink still drives E2E to a delivered outcome (its actual purpose); no flow consumed the logged content. Test updated to assert the redacted shape and that no content values appear.

Verification

• services/notifications: 142 tests pass (incl. new concurrent + redaction tests), tsgo clean, oxlint clean.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Executive Summary

Both review findings from #4627 are addressed correctly: the in-memory in-flight claim closes the concurrent-replay double-send window without a check/await race, and the push-sink log now records only content-free metadata (lengths, key names, a fixed schema-enum discriminator) with no PII.

Files Reviewed (2 files)

• services/notifications/src/dos/NotificationChannelDO.ts
• services/notifications/src/__tests__/dispatch-push.test.ts

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_{Review guidance: REVIEW.md from base branch main}