There is no invitation to accept. On registration they receive a welcome email with the sign-in
link and the centres you assigned. They sign in with that same email address — the platform
recognises them by it.
One exception to know about: if you register them with a creation limit of 0 and no centre
assigned, no email is sent at all. Tell them yourself in that case, or assign a centre first.
✅ Written from capture, 2026-08-27. Fills the gap the checklist flagged as "a gap a new
supervisor would hit immediately". The conditional send is SupervisorManager.java:90
(limit > 0 || !centerIds.isEmpty()) and is raised as product followup 17 — if that is fixed,
delete the exception paragraph.