Polish: npm test runs every test file, two silent failures now log, Loading placeholders shimmer

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

public/style.css

@@ -1200,3 +1200,8 @@ body.qdock #view { padding-right: 340px; }
 
 /* My Store: books ticked for "Add to people" */
 .vcard.picked { outline: 3px solid var(--accent); outline-offset: 2px; border-radius: 12px; }
+
+/* "Loading…" placeholders: a soft shimmer so a slow tab reads as working, not stuck (still text for screen readers; static when motion is reduced) */
+.empty.loading { background: linear-gradient(90deg, transparent 0%, color-mix(in srgb, var(--muted) 16%, transparent) 50%, transparent 100%) 0 0 / 200% 100% no-repeat; animation: loadsweep 1.4s ease-in-out infinite; border-radius: 12px; }
+@keyframes loadsweep { from { background-position: 150% 0; } to { background-position: -50% 0; } }
+@media (prefers-reduced-motion: reduce) { .empty.loading { animation: none; } }