Two transports of the same shape: a main task that hosts the
voice pipeline plus a network-backed `TaskBus` (`RedisBus` or
`PgmqBus`), and a standalone `llm.py` worker process for the
greeter / support LLM. Workers connect to the same bus channel,
register on the shared `TaskRegistry`, and the main task waits
on `runner.registry.watch("greeter", ...)` before sending the
welcome activation so it doesn't fire before the worker is up.
