Fix DinD race condition by waiting for Docker daemon readiness

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Jenkinsfile

@@ -83,6 +83,10 @@ spec:
             steps {
                 container('docker-cli') {
                     sh '''
+until docker info > /dev/null 2>&1; do
+  echo "Waiting for Docker daemon..."
+  sleep 2
+done
 docker build -t rocky-man:${BUILD_NUMBER} .
 docker tag rocky-man:${BUILD_NUMBER} rocky-man:latest
                     '''