Open the shared demo as a signed-in user
Gives the signed-in user a read-only (viewer) membership in the shared demo organization, so they can open it with their own session. Calling it again is safe: an existing membership is kept and the same response is returned. The demo is one dataset shared by everyone; joining adds a membership, never data. A member of the demo sees only their own identity plus the demo’s fictional team, never another real person who joined. The demo does not count toward the 3-organization limit.
Authenticated with a dashboard session (browser cookie), not x-api-key (an API key gets 403), and sends the CSRF token like any other state-changing dashboard request. The request carries no body and does not depend on any organization: a suspended organization, or one that requires two-factor authentication, does not block it. Limited to 10 calls per minute per user. The shared demo guest session cannot call it (the guest is already a member).

