refactor(admin): simplify AdminHeader component by removing inline logic

src/features/admin/pages/DashboardPage.client.js

@@ -1,6 +1,7 @@
 'use client';
 
 import { getWidgets } from '../registry.js';
+import AdminHeader from '../components/AdminHeader.js';
 
 export default function DashboardPage({ stats }) {
   const loading = stats === null || stats === undefined;
@@ -8,10 +9,7 @@ export default function DashboardPage({ stats }) {
 
   return (
     <div className="flex flex-col gap-4 sm:gap-6 lg:gap-8">
-      <div>
-        <h1 className="text-lg sm:text-xl font-semibold text-neutral-900 dark:text-white">Tableau de bord</h1>
-        <p className="mt-1 text-[13px] text-neutral-500 dark:text-neutral-400">Vue d'ensemble de votre application</p>
-      </div>
+      <AdminHeader title="Tableau de bord" description="Vue d'ensemble de votre application" />
       <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 2xl:grid-cols-4 gap-4 sm:gap-6">
         {widgets.map(({ id, Component }) => (
           <Component key={id} data={loading ? null : (stats[id] ?? null)} loading={loading} />