Get Domain Match

Does the caller's verified email domain already have a workspace?

Powers the dashboard's "Join {workspace}" affordance so a teammate sees they're joining their company's existing workspace, not creating a new one. Read-only preview of what POST /orgs/self-serve would auto-join.

Returns {"org": {"id", "name", "slug"}} when a workspace-domain caller with no org yet would auto-join an existing org, else {"org": null} (already a member, consumer email, or no match).