Feat: sécurisation formulaire white paper + stockage leads

- Honeypot, timing check, rate limiting IP, validation serveur
- Déduplication par email : enrichissement des champs vides si contact existant
- Blueprint white-paper : onglet "Contacts intéressés" (champ structure contactDatabase)
- Blueprint site.yml : ajout onglet "Données d'usage" pour vue globale des leads
- Route externalisée dans site/config/routes/download-white-paper.php
- isDownloadable côté client (prénom, nom, email valide, consentement)
- Cursor : pas de hover sur boutons disabled
- Buttons : hover désactivé si disabled

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

site/config/config.php

@@ -13,25 +13,6 @@ return [
     'thumbs' => require __DIR__ . '/thumbs.php',
 
     'routes' => [
-        [
-            'pattern' => ['(:any)/(:any)/download', 'en/(:any)/(:any)/download'],
-            'method'  => 'POST',
-            'action'  => function (string $parent, string $slug) {
-                $page = kirby()->page($parent . '/' . $slug);
-                if (!$page || $page->intendedTemplate()->name() !== 'white-paper') {
-                    http_response_code(404);
-                    header('Content-Type: application/json');
-                    echo json_encode(['error' => 'Not found']);
-                    exit;
-                }
-                // TODO: store/email form data ($kirby->request()->body())
-                header('Content-Type: application/json');
-                echo json_encode([
-                    'success' => true,
-                    'fileUrl' => $page->downloadFile()->toFile()?->url(),
-                ]);
-                exit;
-            }
-        ]
+        require(__DIR__ . '/routes/download-white-paper.php')
     ],
 ];