Add pricing tab switching JS and bmtForm for buy buttons

src/layouts/Base.astro

@@ -603,4 +603,34 @@ const isHome = currentPath === '/';
 
   </div>
 </body>
+<script is:inline>
+// Pricing page: tab switching and BMT Micro form handling
+document.addEventListener('DOMContentLoaded', function() {
+  var nav = document.getElementById('buy-nav');
+  var panels = document.getElementById('buy-panels');
+  if (nav && panels) {
+    var tabs = nav.querySelectorAll('a');
+    var panes = panels.querySelectorAll('.panel');
+    // Show first panel
+    if (panes.length > 0) panes[0].style.display = 'block';
+    // Tab click handlers
+    tabs.forEach(function(tab, i) {
+      tab.addEventListener('click', function(e) {
+        e.preventDefault();
+        tabs.forEach(function(t) { t.classList.remove('current'); });
+        panes.forEach(function(p) { p.style.display = 'none'; });
+        tab.classList.add('current');
+        if (panes[i]) panes[i].style.display = 'block';
+      });
+    });
+  }
+});
+// BMT Micro form submit
+function bmtForm(el) {
+  var form = el.closest('form');
+  var pid = form.querySelector('.product-id');
+  if (pid) pid.value = el.getAttribute('data-value');
+  form.submit();
+}
+</script>
 </html>