A cross-layer workflow passes unit tests but breaks when client, API, and persistence state arrive in a different order. The affected area is notification center.
Repair the notification center request stream implementation so it enforces a per-key sliding window and reports allowed and rejected requests.
Evidence
- Affected surface: Balanced full-stack / notification center.
- Observed failure family: apply a sliding rate window.
- Scope policy: cohort must equal stable.