implement-prepare-environment-script

MEDIUM W011: Third-party content exposure detected (indirect prompt injection risk).

• Third-party content exposure detected (high risk: 0.70). The skill's prepare scripts explicitly run package-install/build commands that fetch code from public package registries (e.g., "pip install -r requirements.txt" in assets/prepare_environment_python.sh and "mvn clean install" in assets/prepare_environment_java.sh), which pulls untrusted, user-published third‑party content into the runtime that can materially affect subsequent build/test behavior.