test(relay): import root fixture shared ownership type

Co-authored-by: Codex <codex@openai.com>
Signed-off-by: Brad Seiler <seiler@squareup.com>

crates/buzz-relay/src/handlers/auth.rs

@@ -2430,6 +2430,7 @@ mod tests {
         #[tokio::test]
         #[ignore = "requires Postgres — runs in postgres-ci nextest lane"]
         async fn durable_ban_revalidates_real_root_admission_without_delivery() {
+            use std::sync::Arc;
             let state = auth_test_state_real_db_expect().await;
             let community = seeded_community(&state).await;
             let (member, owner, agent, bystander) = (