Workflow now passes the GitHub push event's before SHA to the script
via --since, so each release notes run only considers commits added
in this push. Falls back to --latest if the SHA is unavailable
(e.g. first push to a branch). The previous --latest path was
unsafe because amended commits inherit the new committer date and
legitimate body references like "see the #223 release" cause cross
-release grouping via the issue fallback cascade.
Improve the section-heading dedup so the redundant ### **scope**: subject
line is collapsed when its subject is already conveyed by the H1.
Strip the **scope**: / scope: prefix and use a "starts with" match
so multi-commit groupings whose first subject is in the title also
collapse cleanly. Body content is always preserved.
Tested via dry-run with --since HEAD~1, --since <sha>, and
--since HEAD~2 to confirm single, specific, and multi-commit cases
all behave correctly.