Do not expose hidden proposal counts on public case cards

Meeting 15 public case cards reported four proposals for E2E-6-2/4/6, while their public proposal tabs rendered only three published proposals; secretary correctly showed 3/4. The aggregate count reveals the existence of hidden/unpublished proposals. Public counts must use the same visibility scope and authorization rules as the public proposal collection, including hidden-until-published and non-public cases. Add count/detail invariants before, during, and after meeting completion.