About Us: overlay title on the hero images + rename nav item to "About Us"

- Rework the About Us hero so the eyebrow, title and description are overlaid on
  the auto-rotating team images (centred, white, text-shadowed) exactly like the
  landing hero, instead of sitting in a separate white band above them. Remove the
  old page-header band and move its text into the hero. All three languages.
- Rename the "Who We Are" menu item from "Our team" to "About Us"
  (MK "За нас", SI "O nas") across all pages; footer "About us" link unchanged.

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

si/student-welcome-guide/academic-life/index.html

@@ -78,7 +78,7 @@
                     <li class="menu-item menu-item-has-children">
                         <a href="#">O nas</a>
                         <ul class="dropdown-menu">
-                            <li><a href="../../../si/about-us/">Naša ekipa, poslanstvo, vizija in vrednote</a></li>
+                            <li><a href="../../../si/about-us/">O nas</a></li>
                             <li><a href="../../../si/timeline-and-milestones/">Časovnica in dosežki</a></li>
                             <li><a href="../../../si/msos-hub/">MSOS Hub</a></li>
                         </ul>
@@ -137,7 +137,7 @@
             <li class="menu-item menu-item-has-children">
                 <a href="#">O nas</a>
                 <ul class="dropdown-menu">
-                    <li><a href="../../../si/about-us/">Naša ekipa, poslanstvo, vizija in vrednote</a></li>
+                    <li><a href="../../../si/about-us/">O nas</a></li>
                     <li><a href="../../../si/timeline-and-milestones/">Časovnica in dosežki</a></li>
                     <li><a href="../../../si/msos-hub/">MSOS Hub</a></li>
                 </ul>