Add a user by email
POST /v1/api/users - add a member by email (no Slack/Teams needed). Creates
(or re-activates) a workspace_users row on the tenant’s synthetic direct
source with origin='email', signin_access='allowed', then mints a
magic-link invite. Returns the link when no transactional email sender is
wired (so an admin can hand it over).
Authorizations
Personal Access Token. Send as Authorization: Bearer hq_pat_....
Body
Email of the person to add. This is a lookup + dedup attribute only -
the identity key is a stable UUID (external_user_id = workspace_users.id),
so the same human survives an email change. One row per (direct source,
lowercased email); re-inviting updates that row, keeping its UUID.
default (normal member) or granted (tenant-admin from the start).
Response
User added / invited