fairtask-eval: lay out an instance by quoting the decisive lines

[mnkprs]

Why

/fairtask-eval lay out <id> ran npm run show (which only writes examples/<id>/… and prints one line) and then, following the skill's general "show the output verbatim" rule, pasted the whole issue and the test patch into the chat. For a long issue and a diff that is a raw dump; the files are already on disk for anyone who wants the full text.

What changed

• skills/fairtask-eval/SKILL.md: the lay-out row tells the agent to open the three files itself, and step 3 gains an exception for this operation: show the wrote … line, the human labels on one line, then two to four exact quotes with file:line — what the issue asks for, and what the graded tests require that the issue does not say — with a pointer to examples/<id>/ for the full text. Completion: a reader can see the discrepancy (or its absence) without opening the files.
• README §2b: the /fairtask-eval lay out row describes the new behaviour.