Bryan Thompson ae63774678
fix(ci): diff external-PR scope against the merge-base, not base tip
Comparing base-branch-tip -> head made a fork that is behind main report
all of main's later additions as phantom removals/modifications, which
would wrongly fail the scope guard for a legitimate additions-only PR.
Diff merge-base -> head (the PR's actual changes) instead; keep the
"already live" check against the current base branch.

Found by an end-to-end run of evaluate() against real PR data (#3298
stayed clean; #3044's phantom drift collapsed to its real one-line change).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-25 12:18:54 -05:00
..