Round trial artifacts land here as `<round>/<task>/{initial,modified}/entry.vibe`
(+ sibling files for multi-file tasks). Not committed by default (see
`.gitignore` in this directory) — round output is ephemeral working data,
regenerated by re-running a round. Promote a specific pair you want to keep
as a stable reference to `../tasks/<level>/<name>/golden/` instead (see the
main README's "ラウンドの回し方" step 5).
