A background subagent that finishes while its thread is idle starts a
continuation run that sends no prompt and waits for Claude to open a wake
turn. When Claude already read the subagent's result in the turn before, it
never does, and the run stays open until the server restarts.

After the wake buffer is drained without a frame of a wake turn, the run
now waits two minutes for any frame from Claude and settles as completed if
none comes.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>