Completed RLM worker remains active in agent status APIs

[johnrichardrinehart]

Summary

A completed resident RLM worker can remain running in agent roster and observation APIs when its live session retains stale streaming or pending-tool state.

I observed one worker with these conflicting results:

• rlm.list_subagents() reported completed.
• agent_message.list_agents() reported running.
• agent_observe reported status="tool" and isStreaming=true.
• The final child message arrived after the RLM lifecycle had become terminal.

Cause

The RLM lifecycle is persisted in rlm-subagent.json. Passive worker summaries use that record, but resident summaries derive status from live session fields. Stale live fields can therefore override the terminal lifecycle in user-facing results.

Proposed behavior

For an RLM child, the persisted terminal lifecycle must override live activity fields when summaries are created. The resident session can remain available for transcript inspection and later messages, but late messages must not reactivate its reported lifecycle state.

Tested patch

I prepared a focused patch on johnrichardrinehart:fix/stale-worker-status at commit 19ec6fd68.

The patch reconciles resident summaries in agent_message and agent_observe with the persisted lifecycle record. It extends the retained-completed-subagent regression test with stale active, streaming, and unfinished-action state.

Validation passed:

• npm run check
• packages/coding-agent/test/daemon-mode.test.ts: 199 tests passed

The initial pull request was closed automatically because I am not a vouched contributor: #1872. I am posting the issue here as required by CONTRIBUTING.md.