Artifact: ADR-0002/0003 — Polling Superseded by Webhooks

ADR status lifecycle -- an ADR superseded by a new one -- exercises co-07.

ADR-0002: Poll ParcelLink for Shipment Status Every 5 Minutes (original)

Status: Superseded by ADR-0003

Context: (original reasoning: polling was the simplest integration ParcelLink's older API supported at the time.)

Decision: (original: poll every 5 minutes per in-transit shipment.)

Consequences: (original consequences, now superseded -- see ADR-0003.)

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ADR-0003: Use ParcelLink Webhook Push Notifications for Shipment Status

Status: Accepted (supersedes ADR-0002)

Context: polling every in-transit shipment every 5 minutes (ADR-0002) now exceeds ParcelLink's rate limit during peak shipping days, causing missed status updates exactly when customers check most often.

Decision: subscribe to ParcelLink's webhook push API; a shipment's status updates the moment ParcelLink has one, with no per-shipment polling.

Consequences: requires a publicly reachable webhook endpoint and signature verification on incoming payloads; removes the rate-limit ceiling ADR-0002 hit.