style: move menu to button group

Author: essenmitsosse

app/components/AppHeader.vue

@@ -150,7 +150,7 @@ onKeyStroke(
       </div>
 
       <!-- End: Desktop nav items + Mobile menu button -->
-      <div class="hidden sm:flex flex-shrink-0 items-center gap-0.5 sm:gap-2">
+      <ButtonGroup class="hidden sm:flex flex-shrink-0">
         <!-- Desktop: Compare link -->
         <LinkBase variant="button-secondary" to="/compare" keyshortcut="c">
           {{ $t('nav.compare') }}
@@ -162,7 +162,7 @@ onKeyStroke(
         </LinkBase>
 
         <HeaderAccountMenu />
-      </div>
+      </ButtonGroup>
 
       <!-- Mobile: Menu button (always visible, click to open menu) -->
       <ButtonBase

app/components/Header/AccountMenu.client.vue

@@ -62,6 +62,7 @@ function openAuthModal() {
       :aria-expanded="isOpen"
       aria-haspopup="true"
       @click="isOpen = !isOpen"
+      class="rounded-s-none border-s-0"
     >
       <!-- Stacked avatars when connected -->
       <div