Understanding outcomes

Every run ends in one of four outcomes.

Outcome	Meaning
succeeded	The agent returned a result, and the harness's checks passed.
abstained	The agent declined to answer rather than guess.
referred	The matter needs a person's judgement.
failed	The run did not complete, or a check failed.

The app shows, with each outcome, what it means and what to do next.

TODO(#250): link to the outcome vocabulary in the contract once the reference pages are settled.