Convert OpenCode v2 session.next stream events into the existing message part activity path so child sessions that are still producing text, reasoning, or tool output refresh lastUpdate before stale polling runs.
This keeps the timeout poller from cancelling active subagents and preserves tool-call progress for session.next.tool.called events.
Plan: .omo/plans/subagent-timeout-active-output.md
YeonGyu-Kim