test(scripts): add summary modes to validation tests

scripts/test-build-validation.sh

@@ -1,5 +1,12 @@
 #!/usr/bin/env bash
 set -euo pipefail
+summary=false
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --summary) summary=true; shift ;;
+    *) printf 'Unknown argument: %s\n' "$1" >&2; exit 1 ;;
+  esac
+done
 
 root=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)
 work=$(mktemp -d)
@@ -45,4 +52,4 @@ mutate_leftover_placeholder() {
 }
 test_build_fails 'leftover template placeholder' mutate_leftover_placeholder
 
-printf 'PASS build validation: invalid JSON, duplicate agent, duplicate plugin, and leftover placeholders are all rejected\n'
+if [ "$summary" = true ]; then printf 'Tests: PASS | build validation\n'; else printf 'PASS build validation: invalid JSON, duplicate agent, duplicate plugin, and leftover placeholders are all rejected\n'; fi