v0.6.16

feat(peer): auto-update Linux hosts when idle

Add a setting, on by default, that runs the SSH installer on any connected
Linux host whose lpm version is older than the app's. A host waits while its
agents are running or waiting. A failed update is retried after 30 minutes,
and auto-update stops trying that release after 3 failures. The host row
shows when an update is running and why the last one failed, and only one
install or uninstall can run on a host at a time.