refactor: update JSON parsing to ensure type safety for ID fields in models

lib/features/company/models/company_model.dart

@@ -35,9 +35,9 @@ class CompanyModel extends Equatable {
 
   factory CompanyModel.fromJson(Map<String, dynamic> json) {
     return CompanyModel(
-      id: json['id'],
+      id: json['id'] as String,
       createdAt: DateTime.parse(json['created_at']),
-      userId: json['user_id'],
+      userId: json['user_id'] as String,
       ragioneSociale: json['ragione_sociale'],
       indirizzo: json['indirizzo'],
       cap: json['cap'],

lib/features/customers/models/customer_file_model.dart

@@ -1,7 +1,7 @@
 import 'package:equatable/equatable.dart';
 
 class CustomerFileModel extends Equatable {
-  final int? id;
+  final String? id;
   final String customerId; // Riferimento UUID
   final String name;
   final String url;
@@ -19,7 +19,7 @@ class CustomerFileModel extends Equatable {
 
   factory CustomerFileModel.fromJson(Map<String, dynamic> json) {
     return CustomerFileModel(
-      id: json['id'],
+      id: json['id'] as String,
       customerId: json['customer_id'],
       name: json['name'],
       url: json['url'],

lib/features/store/models/store_model.dart

@@ -69,9 +69,9 @@ class StoreModel extends Equatable {
 
   factory StoreModel.fromJson(Map<String, dynamic> json) {
     return StoreModel(
-      id: json['id'],
+      id: json['id'] as String,
       nome: json['nome'],
-      companyId: json['company_id'],
+      companyId: json['company_id'] as String,
       isActive: json['is_active'] ?? true,
       isPaid: json['is_paid'] ?? false,
       paymentExpiration: json['payment_expiration'] != null