Readonlystate: CSLive agent state (built-in + custom slices).
Tears down by resetting all state slices that have a reset() method.
Where the data tools' generated code runs now. In a browser, unavailable (code fails) and
main-thread (code runs unisolated) both mean the iframe sandbox couldn't start.
The return type of createMapAgent(), a real ToolLoopAgent instance with state access and cleanup.