(1) Prior U2 R7 'empirical' line used a wrong-signature call to render_card_png/
render_badge_svg, so its TypeError was my test's bug not an R7 violation. Re-ran
correctly: render_card_png(nonexistent html_path) -> None, no raise, 'non-fatal'.
R7 holds (empirical + structural). U2 verdict UNCHANGED, still PASS.
(2) Eyeballed the real served u1-uk-shot summary.png — content matches results.json.
(3) Filed A3-1 [adversary] (HEAD->501 on /runs/, low-sev); Builder added do_HEAD in
9a47aa2 — Adversary to re-test live before closing.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>