fix(a11y): activities tablist must contain only tabs

The "Become a member" CTA was a direct child of role="tablist", which
violates the ARIA rule that a tablist may only contain role="tab" children
(axe: aria-required-children). Wrap the 4 tabs in an inner
.activities-tabs[role=tablist] and leave the CTA as a sibling; add matching
flex CSS so the layout is unchanged. JS uses `.activities-nav .activity-tab`
(descendant), so tab behavior is unaffected. EN/MK/SI. Cache-bust bump.

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

en/index.html

@@ -60,7 +60,7 @@
     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.1/css/all.min.css" integrity="sha512-DTOQO9RWCH3ppGqcWaEA1BIZOC6xxalwEsw9c2QQeAIftl+Vegovlnee1c9QX4TctnWMn13TZye+giMm8e2LwA==" crossorigin="anonymous" referrerpolicy="no-referrer" media="print" onload="this.media=&#39;all&#39;" /><noscript><link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.1/css/all.min.css" integrity="sha512-DTOQO9RWCH3ppGqcWaEA1BIZOC6xxalwEsw9c2QQeAIftl+Vegovlnee1c9QX4TctnWMn13TZye+giMm8e2LwA==" crossorigin="anonymous" referrerpolicy="no-referrer" /></noscript>
 
     <!-- Link to the main CSS file (corrected path) -->
-    <link rel="stylesheet" href="../css/main.css?v=cd97d474">
+    <link rel="stylesheet" href="../css/main.css?v=54203d0c">
     <link rel="preload" as="image" href="../images/HeroSection-img1.webp">
 </head>
 <body>
@@ -276,7 +276,8 @@
                 <p>From your first application to graduation, we’re by your side, support, friendships, culture, and a voice that speaks up for Macedonian students in Slovenia.</p>
             </div>
             <div class="activities-content">
-                <div class="activities-nav" role="tablist" aria-label="Activities">
+                <div class="activities-nav">
+                    <div class="activities-tabs" role="tablist" aria-label="Activities">
                     <button type="button" class="activity-tab active" role="tab" aria-selected="true" data-panel="0">
                         <span class="activity-tab-ico"><i class="fas fa-hand-holding-heart" aria-hidden="true"></i></span>
                         <span class="activity-tab-label">Student Support</span>
@@ -293,6 +294,7 @@
                         <span class="activity-tab-ico"><i class="fas fa-bullhorn" aria-hidden="true"></i></span>
                         <span class="activity-tab-label">Student Representation</span>
                     </button>
+                    </div>
                     <a href="../en/become-a-member/" class="btn btn-primary-orange activities-cta">Become a member</a>
                 </div>
                 <div class="activities-panels">
@@ -546,8 +548,8 @@
 </footer>
 <!-- END_FOOTER -->
 
-    <script src="../main.js?v=cd97d474"></script>
-<link rel="stylesheet" href="/assistant.css?v=cd97d474">
-<script src="/assistant.js?v=cd97d474" defer></script>
+    <script src="../main.js?v=54203d0c"></script>
+<link rel="stylesheet" href="/assistant.css?v=54203d0c">
+<script src="/assistant.js?v=54203d0c" defer></script>
 </body>
 </html>