Add optional startDate/endDate columns to prescriptions (schema,
validation, types, service) — when set, endDate drives expiry.
Add a new append-only `dispenses` resource (schema, types, validation,
service, route at /api/dispenses) recording who received which medication,
gated on the existing inventory RBAC statement. Migration 0020.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Khalid Abdi