Roster sync service

A client-side directory (imagine a school's SIS) kept in sync from member.joinedand member.removed webhooks. Each delivery is signature-verified, then applied to a local directory as an immutable state update.

Webhooks can be missed — a dropped delivery, downtime, or a race means the directory can drift from the source of truth. That's why real integrations pair webhooks with a periodicreconcile pull: fetch the live member list and diff it against the local copy. Trigger a join or leave to drive the sync, then hit Reconcile now to check for drift.