Directory sync checks the remote machine is alive before forwarding a command

What

When a session uses directory sync (keeping files in step with another machine, such as your own computer), commands are forwarded to that machine. Before forwarding, Claude Code can now check that the machine is still there.

• The check calls the transport's checkLive when the sync engine supports pushPoint.
• If the machine is offline, or has been silent too long and misses the probe, it is marked away, the outcome is away, and the call fails without sending anything.
• The error says the machine did not answer a liveness check and that nothing was sent. The failure is attributed to the machine ("machine") rather than "this_side", and recorded with clearance machine_away.
• Before, the command went straight to waiting for in-flight syncs and forwarding.

Why

Commands no longer hang against a machine that has gone away, such as a laptop that was closed, and the error makes clear the problem is on that machine's side.