update

assets/js/app.js

@@ -285,10 +285,32 @@
         return queueConfirm(message, options);
     };
 
+    function initSidebarCollapse() {
+        var collapseBtn = document.getElementById('js-sidebar-collapse');
+        var appShell = document.getElementById('js-app-shell');
+        var backdrop = document.getElementById('js-sidebar-backdrop');
+        if (!collapseBtn || !appShell) return;
+
+        var saved = localStorage.getItem('backpro_sidebar_collapsed');
+        if (saved === '1') appShell.classList.add('is-collapsed');
+
+        collapseBtn.addEventListener('click', function () {
+            appShell.classList.toggle('is-collapsed');
+            localStorage.setItem('backpro_sidebar_collapsed', appShell.classList.contains('is-collapsed') ? '1' : '0');
+        });
+
+        if (backdrop) {
+            backdrop.addEventListener('click', function () {
+                appShell.classList.remove('sidebar-open');
+            });
+        }
+    }
+
     document.addEventListener('DOMContentLoaded', function () {
         installConfirmForForms();
         initTestConnectionButtons();
         initTopicEditButtons();
         highlightActiveSidebarLink();
+        initSidebarCollapse();
     });
 })();