Wireframe for #15426 — Add-backend chooser reduced to two paths: Agent-server & Cloud. No Local/Remote split: Agent-server just takes the real connection fields it uses today (URL + optional session API key). No "Enterprise" wording in the modal — just a subtle deployment-docs link. Low-fidelity on purpose — for discussion, not final visuals.

Fields shown match today's agent-server onboarding (URL + optional Session API key). Open for the thread: footer deployment-docs link vs a lightweight third row; exact footer copy is a placeholder ("More about deployment options" / "Deployment docs").