ci: enforce changelog attribution policy in pr gates

scripts/pr-lib/changelog.sh

@@ -155,6 +155,10 @@ if (updated !== original) {
 EOF_NODE
 }
 
+validate_changelog_attribution_policy() {
+  node scripts/check-changelog-attributions.mjs CHANGELOG.md
+}
+
 validate_changelog_entry_for_pr() {
   local pr="$1"
   local contrib="$2"

scripts/pr-lib/gates.sh

@@ -60,6 +60,7 @@ prepare_gates() {
 
   if [ "$has_changelog_update" = "true" ]; then
     normalize_pr_changelog_entries "$pr"
+    validate_changelog_attribution_policy
   fi
 
   if [ "$changelog_required" = "true" ]; then