Clerk dev instance
The shared Clerk dev instance both backend and portal test against — required dashboard config and instance-separation rules.
Clerk webhook relay
How Clerk events reach a localhost backend — the pinned relay token, Svix endpoint registration, and the round-trip check.
Deployed test stack
What the optolink-test Heroku stack is, what runs on it, and how to operate it (access, DB, Clerk-instance separation, write-safety).