Member Portal API — SENTINEL (root)

Node/Express backend, in-memory store. This spec is bounded and navigable: read this root and enter each node. Each node is a set of requirements that MUST end up 100% satisfied — you do not need to load everything at once; navigate node by node and satisfy them all.

Node	Covers
members.md	Create, validation, duplicates, paginated list, read, delete (R1–R5, R11)
activity-admin.md	Activity recording + admin aggregated dashboard (R6, R7, R12)
ops.md	Health, consistent error shape, timestamps (R8–R10)

Rule: no node is optional. The acceptance criterion of each node is part of the contract.