Switch every example to ``await runner.spawn(task)`` followed by
``await runner.run()`` (no task argument), and ``await runner.cancel()``
on client-disconnected instead of ``await task.cancel()``. This makes
the main pipeline task look the same as the worker / proxy tasks
spawned alongside it, and lets ``runner.cancel()`` drive a uniform
shutdown across every root task on the bus.
Voice code assistant that dispatches questions to a Claude Agent
SDK worker. The main task runs the voice pipeline (STT + LLM + TTS)
and an `ask_code` direct function. `CodeWorker` is a bus-only
`BaseTask` spawned on the runner: it accepts `@job`-style
requests through the bus, queues them onto an asyncio queue, and
runs them sequentially through a persistent Claude SDK session so
follow-ups share context. The example shows the job-RPC surface
(`task.job("code_worker", ...)`), bus-only tasks (no pipeline),
and the `pipeline_task` field on `FunctionCallParams`.
