- refetch.js: fetch one article via its source recipe on the site-shared
  browser instance; refresh 原文.md in place for already-archived articles
  (registry ownership-checked, index rebuilt from registry) and re-push
  via push.js --url; new URLs archive to today's dir pending summaries.
  Busy site locks are respected; only self-launched instances are recycled.
- push.js: --url <articleUrl> re-pushes a single article (query/hash
  normalized match, ledger ignored for it); recordResult now appends a
  ledger entry when the article postdates the ledger instead of silently
  dropping a successful push result (refetch-into-finalized-day case).
- harvest.js: export downloadImage/normalizeUrl for refetch.