Add baseline comparison to detect-duplicates.py: when DIFF_BASE is set
(via CI_COMMIT_TARGET_BRANCH for PRs), the script compares findings
against the base branch and only fails on new duplicates introduced by
the PR. Pre-existing duplicates are reported as informational.
For push events (no DIFF_BASE), the script reports all findings but
exits 0 (informational only). Removes failure:ignore from the CI step
so new duplicates properly block PRs.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
5e4b00f9a3