The command-only settle probe dropped a failed `get_state` on the floor.
Pi emits no agent events for a pure extension command, so the turn stayed
active and the session rejected every later turn until restart.

The probe now queues a `probeFailed` record instead of swallowing the
error, so the same ordered handler settles the turn. The existing
no-agent-activity guard still keeps a genuinely running turn open.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>