Stream a run's events

Streams an agent run as Server-Sent Events (text/event-stream): the frames of its session's telemetry that belong to the run, the model's text as it streams (model_delta logs), and the run's own events, live as the run runs. Each event's id is its resume cursor, its event name is the frame kind (span or log), and its data is the frame JSON. The run's events are logs: run_status (attribute axilio.run.status: running when the run starts on its phone or goes back to running), run_input_required (it paused for a person; the body is the question, with the input request's id, reason, requested_by, response_schema and expires_at as attributes), run_resumed (a person answered; the body is the action), run_result (how it ended on the phone: axilio.ok, axilio.run.output or axilio.run.error, and the summary as the body), and user_message (a person's message reached the run; the body is the message). The stream's last event is a run_status with the run's final status as the run itself has it (completed, failed or cancelled), so a run the caller cancelled ends cancelled. These events are not archived; the run itself has the result. A session started with telemetry off still streams its run's events and the model's text, and nothing else. A new reader (or one whose cursor is older than the live window) first receives the run's archived frames and then the live ones, deduplicated on span id and phase, followed by an event with no data that carries the cursor the replay ended at. Reconnect with the Last-Event-ID header to resume. The model's text is not archived: a reader that reconnects after it left the live window gets the step's answer from the run's steps instead. A comment line is sent every 15 seconds while the stream is idle. The stream closes after the run's final status; a reconnect after the end with nothing left gets 204. A run that has not reached a phone yet streams only comments until it does. Authenticate with the API key header, or open the run's stream_url, which carries a read-only token for the run's session. Org-scoped: another org's run reads as not found. Readers MUST ignore events with an unknown name, unknown fields, and unknown span_type or log_type values.