stop-notify-external-failure

When an external dependency (tool, binary, package) cannot be downloaded or installed from its canonical source (GitHub Releases, PyPI, npm registry, etc.), STOP immediately and notify the user instead of improvising workarounds. Use when Kimi is asked to download, install, or use an external tool and the download/install step fails for any reason (network timeout, 404, DNS failure, rate limit, proxy issue, etc.). Also use when Kimi is tempted to write a homemade replacement, try brute-force alternatives, or proceed without the requested tool.