tasks: figure out what to do when a workspace is stopped

[bpmct]

One idea:

related to coder/registry#127

[BrunoQuaresma]

I think we can:

• Display a "Rerun task" if the latest activity status was a success
• Display the statuses returned from the agent like a history

Not sure if we have the necessary data to make that happen tho.

[bpmct]

• "resume task" makes sense to me