List sendable RCS cards for the LiveChat composer
Returns the workspace's registered card templates (id, label, card preview) so an agent can pick one in the composer. Gated by RCS_MESSAGING + workspace_rcs_config; returns an empty list (rcsEnabled:false) when RCS is off. Authenticated workspace agent (Bearer).
GET
https://api.channelautomation.com/api/rcs/workspaces/{workspaceId}/agent-templates