Function cleanup

src/screens/REPL.tsx:2300–2303

()

          // the remote prompt and unsubscribe when the local user
          // responds first.
          const cleanup = () => {
            unsubscribe();
            bridgeCallbacks.cancelRequest(bridgeRequestId);
          };
          const existing = sandboxBridgeCleanupRef.current.get(hostPattern.host) ?? [];
          existing.push(cleanup);
          sandboxBridgeCleanupRef.current.set(hostPattern.host, existing);