chore(admin-ui): rename overview to dashboard and remove frontend link

resources/views/admin/layouts/app.blade.php

@@ -15,7 +15,7 @@
             <a class="topnav-brand" href="/admin">SaaSShop</a>
 
             <nav class="topnav-menu" aria-label="总台主导航" data-role="topnav-groups-root">
-                <a class="topnav-link" href="/admin">总览</a>
+                <a class="topnav-link" href="/admin">仪表盘</a>
 
                 <details class="topnav-item nav-group" data-role="topnav-group">
                     <summary class="topnav-summary nav-group-title">收费中心</summary>
@@ -59,7 +59,6 @@
             </nav>
 
             <div class="topnav-actions">
-                <a class="topnav-link" href="/">返回前台</a>
                 <form method="post" action="/admin/logout" class="logout-form topnav-logout">@csrf <button type="submit" class="btn btn-secondary btn-sm">退出登录</button></form>
             </div>
         </div>