Weekly trend workflow: runs the full iptv-checker weekly, keeps a
snapshot of failed URLs in .github/checker-history/failed.txt, and
reports newly-broken vs newly-recovered channels since the last run
in the job summary.
PR check workflow: on any PR touching lists/*.md, extracts only the
added/changed stream links from the diff and checks just those (not
the whole 2000+ channel playlist), reporting online/failed results
directly in the PR's Checks summary.
Kálmán „KAMI” Szalai