UI styling improvements: dashboard headers and navigation

- Restore blue PageHeader on Dashboard (/app-components)
- Update homepage (/) with subtle header design without blue bar
- Add uniform PageHeader styling to application edit page
- Fix Rapporten link on homepage to point to /reports overview
- Improve header descriptions spacing for better readability

frontend/src/components/UserManagement.tsx

@@ -1,6 +1,7 @@
 import { useState, useEffect } from 'react';
 import { useHasPermission } from '../hooks/usePermissions';
 import ProtectedRoute from './ProtectedRoute';
+import PageHeader from './PageHeader';
 
 const API_BASE = import.meta.env.VITE_API_URL || 'http://localhost:3001';
 
@@ -318,21 +319,26 @@ export default function UserManagement() {
   return (
     <div className="space-y-6">
       {/* Header */}
-      <div className="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-4">
-        <div>
-          <h1 className="text-3xl font-bold text-gray-900">Gebruikersbeheer</h1>
-          <p className="text-gray-600 mt-1">Beheer gebruikers, rollen en rechten</p>
-        </div>
-        <button
-          onClick={() => setShowCreateModal(true)}
-          className="inline-flex items-center gap-2 px-5 py-2.5 bg-blue-600 text-white font-medium rounded-lg hover:bg-blue-700 transition-colors shadow-sm hover:shadow-md"
-        >
-          <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 4v16m8-8H4" />
+      <PageHeader
+        title="Gebruikersbeheer"
+        description="Beheer gebruikers, rollen en rechten"
+        icon={
+          <svg className="w-8 h-8" fill="none" viewBox="0 0 24 24" stroke="currentColor">
+            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 4.354a4 4 0 110 5.292M15 21H3v-1a6 6 0 0112 0v1zm0 0h6v-1a6 6 0 00-9-5.197M13 7a4 4 0 11-8 0 4 4 0 018 0z" />
           </svg>
-          Nieuwe gebruiker
-        </button>
-      </div>
+        }
+        actions={
+          <button
+            onClick={() => setShowCreateModal(true)}
+            className="px-4 py-2 bg-white text-blue-600 rounded-lg hover:bg-blue-50 transition-colors font-medium text-sm shadow-sm hover:shadow-md flex items-center gap-2"
+          >
+            <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 4v16m8-8H4" />
+            </svg>
+            Nieuwe gebruiker
+          </button>
+        }
+      />
 
       {/* Success/Error Messages */}
       {success && (