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/ContractController.php

@@ -3,7 +3,7 @@
 namespace App\Http\Controllers;
 
 use Illuminate\Http\Request;
-use App\User;
+use App\Models\User;
 use Carbon\Carbon;
 use OneSignal;
 use Openpay;
@@ -13,7 +13,7 @@ use OpenpayApiAuthError;
 use OpenpayApiRequestError;
 use OpenpayApiConnectionError;
 use OpenpayApiTransactionError;
-use App\iChambaParameter;
+use App\Models\iChambaParameter;
 use App\Models\Suppliers;
 use App\Models\Categories;
 use App\Models\Cards;