Implement replay-safe browser synchronization

crates/remora-api/tests/public_api.rs

@@ -144,6 +144,8 @@ impl Harness {
                 event_retention: Duration::from_secs(60),
                 event_poll_interval: Duration::from_millis(50),
                 event_heartbeat_interval: Duration::from_secs(1),
+                event_ticket_ttl: Duration::from_secs(30),
+                event_allowed_origins: vec!["https://remora.test".into()],
             },
         )
         .unwrap();