Fix export type hint, dark mode import page, documentation

- Corrige le type de retour de UserController::export() (StreamedResponse)
- Ajoute les classes dark mode manquantes sur le bloc info de la page import
- Génère la documentation complète du projet dans docs/documentation.md

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

app/Http/Controllers/Admin/UserController.php

@@ -9,6 +9,7 @@ use App\Support\DbCompat;
 use Illuminate\Http\RedirectResponse;
 use Illuminate\Http\Request;
 use Illuminate\Http\Response;
+use Symfony\Component\HttpFoundation\StreamedResponse;
 use Illuminate\Support\Facades\Hash;
 use Illuminate\Support\Str;
 use Illuminate\Validation\Rules\Enum;
@@ -48,7 +49,7 @@ class UserController extends Controller
 
     // ── Export CSV ────────────────────────────────────────────────────────────
 
-    public function export(Request $request): Response
+    public function export(Request $request): StreamedResponse
     {
         $query = User::with('sections')->orderBy('name');