Same async-tool routing approach as #4441: detect async-tool messages in
the LLM context, deliver the final result via the formal tool-result
channel.
Caveat: as of this writing, Inworld Realtime doesn't appear to handle
the resulting delayed tool result reliably, so the routing is
best-effort and the service emits a one-time warning when async-tool
messages are seen. Streamed intermediate results remain unsupported.
Also adds function calling to the realtime-inworld.py example, and
softens the Inworld mention in the #4447 changelog now that the
exclusion is being closed.
58333b2705