ci: wait for staging to be healthy before audit

Jenkinsfile

@@ -178,6 +178,28 @@ PY
                 '''
             }
         }
+        stage('Wait For Staging Health') {
+            agent { label 'built-in' }
+            options {
+                timeout(time: 5, unit: 'MINUTES')
+            }
+            steps {
+                sh '''
+                    set -e
+                    for i in $(seq 1 30); do
+                        code_nl=$(curl -sS -o /dev/null -w "%{http_code}" https://mandelstudio.welkombij.mandelblog.com/ || true)
+                        code_en=$(curl -sS -o /dev/null -w "%{http_code}" https://mandelstudio.welkombij.mandelblog.com/en/ || true)
+                        echo "healthcheck attempt=$i nl=$code_nl en=$code_en"
+                        if [ "$code_nl" = "200" ] && [ "$code_en" = "200" ]; then
+                            exit 0
+                        fi
+                        sleep 10
+                    done
+                    echo "staging did not become healthy in time"
+                    exit 1
+                '''
+            }
+        }
         stage('Post-Deploy Multilingual Audit') {
             agent { label 'built-in' }
             options {