Signup registers/binds a Verae central user and stores veraeUserId. Public access stays the zappier API key. Chain JWTs stay server-side behind tokenRef. Authz, billing, and jobs.watch carry veraeUserId.
Zapier is one ingress. Direct web, customer API, and S2S leaf nodes are their own services. Every hop to an internal subject must pass verae.access.authz.check (default deny by plane).