[Bug]: Parent thread shows done while its child's subagents are still running#33482

Area: apps/server

Steps

1. Thread A starts task B with delegate_task. B finishes.
2. A sends B a follow-up with t3_thread_send.
3. In that follow-up, B starts task C with delegate_task (async) and ends its turn.

Expected: A shows Waiting until C finishes.

Actual: A shows as done (no Working or Waiting) while C is still running. A delegate_task wait on A also returns result_available early.

If B starts C in its first turn instead, it works.

Cause: finalizeAppOwnedSubagent (Orchestrator.ts:13087) keeps only the child's first record open while it is waiting_for_children. The follow-up record closes when B's turn ends.

Version: 0.1.8-nightly.20261109.4399, macOS, Claude provider