feat: add talk_message_stream

[sebvanleuven]

Empty PR to trigger alpha release.

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Summary by cubic

Adds talk_message_stream to support streaming messages when bypassing the default LLM. This enables clients to handle streamed output directly.

• New Features
  • Introduces talk_message_stream for LLM bypass streaming.
  • No changes to existing talk_message; remains backward compatible.

^{Written for commit d0ea511. Summary will update on new commits.}