v2.29.0: Snapshots on a schedule, and a job that stops gets noticed

• Snapshots can now be taken on a schedule. Ask the skill to keep tracking something and it sets
  up a daily or weekly job for Windows, macOS or Linux. You see it and approve it before anything is
  registered.
• You hear about a scheduled job that stops or fails. Each run is recorded, failures included, and
  the next session says when a job has stopped, keeps failing, or is waiting on another stack.
• A job collects for one stack only. While another stack is active it writes nothing, and
  switching stacks tells you so.
• "Start tracking X" now says whether anything will measure it. Before, a metric could be
  registered with nothing ever taking a snapshot.