feat(backoffice): Create a nested/dropdown sidebar list

- Create a dropdown sidebar list
- Show back the old navigation and group them
- Make the sidebar responsive for mobile view

apps/backoffice/src/app/(protected)/layout.tsx

@@ -1,13 +1,51 @@
-import { FC, ReactElement } from 'react';
+import { FC, ReactElement, useState } from 'react';
 import { Outlet } from 'react-router-dom';
 import { BackofficeSidebar } from '@imphnen-frontend-service/ui/organisms';
 
 export const AppLayout: FC = (): ReactElement => {
+  const [mobileSidebarOpen, setMobileSidebarOpen] = useState(false);
+
   return (
     <div className="bg-primary-50 min-h-screen flex justify-center">
       <div className="bg-primary-50 min-h-screen w-full flex">
-        <BackofficeSidebar />
+        <BackofficeSidebar
+          isOpen={mobileSidebarOpen}
+          onClose={() => setMobileSidebarOpen(false)}
+        />
         <div className="flex-1 overflow-auto">
+          {/* Sticky top header */}
+          <header
+            className={
+              'sticky top-0 bg-white border-b border-primary-200 px-4 py-3 flex items-center gap-3 ' +
+              (mobileSidebarOpen ? 'z-0' : 'z-30')
+            }
+          >
+            {/* Mobile menu button (shown on small screens) */}
+            <button
+              type="button"
+              className="md:hidden p-2 rounded-md hover:bg-gray-100 text-gray-700"
+              onClick={() => setMobileSidebarOpen(true)}
+              aria-label="Open sidebar"
+            >
+              <svg
+                className="w-5 h-5"
+                fill="none"
+                stroke="currentColor"
+                viewBox="0 0 24 24"
+              >
+                <path
+                  strokeLinecap="round"
+                  strokeLinejoin="round"
+                  strokeWidth={2}
+                  d="M4 6h16M4 12h16M4 18h16"
+                />
+              </svg>
+            </button>
+            <h1 className="text-p3 font-semibold text-primary-700">
+              IMPHNEN Backoffice
+            </h1>
+          </header>
+
           <Outlet />
         </div>
       </div>

apps/backoffice/src/index.css

@@ -130,7 +130,7 @@
   html {
     font-family: 'Bai Jamjuree', sans-serif;
     font-weight: 400;
-    font-size: 12px;
+    font-size: 14px;
     line-height: 1.2;
   }
-}
+}