Run agent synchronously

Execute an agent run in a blocking manner and return the complete result once finished. A run still going after 8 minutes keeps running, and the request returns 202 Accepted with code run_still_running, the runId, and a Location header pointing at /api/agents/:agentId/run-async/:runId/status; poll it (after Retry-After seconds) and read /api/agents/:agentId/run-async/:runId/result once it is done. Use /api/agents/:agentId/run-async for runs that can take longer.