style(qa3): design-token foundation + safe polish/a11y fixes

- Add :root design tokens in _typography.css (was empty) — brand teal/orange,
  ink/text greys, radius + type scale + section rhythm. Visually neutral;
  new rules can reference var()s instead of scattered literals.
- a11y: visible :focus-visible ring on header nav + dropdown links (keyboard
  users had none).
- Fix synthesized faux-bold: .route-report h1 800 -> 700 (Inter loads 400-700).
- Testimonials column: overflow-y scroll -> auto (no permanent scrollbar gutter).
- Lightbox image radius 6px -> 8px (matches the site rounding scale).
- Consistent card affordance: homepage .news-card now lifts on hover like the
  news-hub / blog cards.
- Re-stamped cache-bust (v=1f64b22f).

Deferred (needs a brand decision): unifying the two primary oranges
(#FA7850 vs #F2762E) and the fuller literal->token migration.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

css/layout/_header.css

@@ -95,6 +95,12 @@
 .navigation > .menu-item > a:hover {
     color: #101828;
 }
+.navigation > .menu-item > a:focus-visible {
+    outline: 2px solid var(--teal);
+    outline-offset: 3px;
+    border-radius: 4px;
+    color: #101828;
+}
 
 /* Poudarjanje aktivne strani na namizju */
 .navigation .menu-item.active-page > a {
@@ -237,9 +243,11 @@
     white-space: nowrap;
 }
 
-.dropdown-menu a:hover {
+.dropdown-menu a:hover,
+.dropdown-menu a:focus-visible {
     background-color: #F9FAFB;
     color: #2D738C;
+    outline: none;
 }
 
 .mobile-menu-icon, .mobile-nav-panel {