Explore options for refreshing a task's up-to-date status

[pd93]

Currently, the task tree in the sidebar is only updated when we detect a change to a Taskfile or the user manually refreshes it. However, a task's up-to-date status can change at any time - for example if a task's sources or a condition in a task's status changes.

Here are some initial thoughts. Some of which may or may not compliment one another:

• Update the task list after running a task
• Periodically update the task list
  • This would probably be controlled by a setting to enable/disable polling and adjust the refresh period
• Update the task list when any file changes
• Update the task list when sources/generates change.