Upgrade: Laravel 11, consolidación modelos App\Models\

- Actualización a Laravel 11.47.0
- Migración de modelos a namespace App\Models\
- Actualización de todos los controladores
- Actualización de configuraciones
- Documentación README.md

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/Http/Controllers/PaymentController.php

@@ -5,7 +5,7 @@ namespace App\Http\Controllers;
 use Illuminate\Http\Request;
 use Illuminate\Support\Facades\Validator;
 use Carbon\Carbon;
-use App\User;
+use App\Models\User;
 use App\Models\Suppliers;
 use App\Models\Payments;
 use App\Models\FinishedContracts;
@@ -18,8 +18,6 @@ use OpenpayApiRequestError;
 use OpenpayApiConnectionError;
 use OpenpayApiTransactionError;
 
-require_once '../vendor/autoload.php';
-
 class PaymentController extends Controller
 {
     //