Demonstrates that agent.observe(runId, {}) delivers the tool-call-suspended chunk and then
stays open forever on @mastra/core 1.83.0-alpha.1, while the runner's own stream() with
closeOnSuspend: true closes cleanly. Also demonstrates that the only built-in way to terminate
the observer, idleTimeoutMs, ends the stream with an error chunk instead of a clean close.
- Expected: an opt-in (e.g.
observe(runId, { closeOnSuspend: true })) closes the observer