fix(transport-http): stream /chat response instead of buffering

The /chat endpoint was buffering the entire turn before returning
the response, which meant X-Conversation-Id was not available until
the turn finished. This prevented the CLI --open flag from firing
until after the turn completed.

Now the response is a ReadableStream that:
- Returns X-Conversation-Id header immediately
- Streams NDJSON events as they arrive from the orchestrator
- Closes the stream when the turn completes (or errors)
- Records throughput after stream close (non-blocking)

This fixes: dispatch <model> --text '...' --open now opens the
frontend tab immediately, not after the turn finishes.

0 files changed, 0 insertions, 0 deletions