Web chat protocol

python -m osa_tool.run_chat --web-chat runs the agent graph over JSON lines. The normal terminal command remains interactive. Web mode reserves stdout for protocol events and writes diagnostics to stderr and OSA log files. Supply --output DIR for a per-run workspace and --log-dir DIR for logs.

Send one JSON object per line to stdin. The first message is:

{"type":"start","repository":"https://github.com/owner/repo","request":"Improve the README","attachment":null}

OSA sends started, progress, review, question, completed, stopped, or error events. A question has an id, question, kind, and fields array. Answer it with:

{"type":"answer","id":"QUESTION_ID","values":{"field_name":"value"}}

Answer IDs must match the pending question. Required fields need nonempty text; review approval accepts yes or no. Invalid answers produce a recoverable error and leave the question pending. A {"type":"cancel"} message stops a run while it is awaiting input; clients should terminate the process group to cancel work in progress.

completed contains a summary, task IDs, statuses and results, artifact paths within the requested output directory, and any pull request URL. stopped includes a reason. A rejected review at the revision limit stops without finalizing or publishing. A terminal error has recoverable: false and the process exits nonzero.