enhance: Enhances backorder confirmation API

Updates the `createBackorderConfirmation` API call to dynamically specify whether to create a backorder (reliquat) or not.

Introduces a `toBackorder` parameter, enabling the API to handle both "with backorder" and "without backorder" scenarios based on user selection. This centralizes the backorder status setting within a single API call.

Additionally, adds loading indicators to the backorder dialog buttons for improved user feedback during the confirmation process.

lib/backend/api/api_calls.dart

@@ -413,6 +413,7 @@ class ApiCalls {
   /// either `withBackorder()` or `withoutBackorder()`.
   static Future<int?> createBackorderConfirmation({
     required int stockPickingId,
+    required bool toBackorder,
   }) async {
     try {
       final response = await dioService.post(
@@ -440,7 +441,8 @@ class ApiCalls {
                     0,
                     {
                       "picking_id": stockPickingId, // stock picking id
-                      //"to_backorder": false // true = avec reliquat / false = sans reliquat
+                      "to_backorder":
+                          toBackorder, // true = avec reliquat / false = sans reliquat
                     },
                   ],
                 ],

lib/components/backorder_dialog_component.dart

@@ -42,6 +42,7 @@ class DeleteCategorieDialogComponentWidget extends ConsumerWidget {
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
+    final state = ref.watch(receptionDetailsPageModelProvider);
     return Container(
       width: double.infinity,
       decoration: BoxDecoration(
@@ -74,6 +75,7 @@ class DeleteCategorieDialogComponentWidget extends ConsumerWidget {
                 children: [
                   Expanded(
                     child: PrimaryButtonComponent(
+                      loading: state.withBackorderLoading,
                       text: 'Créer un reliquat',
                       onPressed: () async {
                         await ref
@@ -89,6 +91,7 @@ class DeleteCategorieDialogComponentWidget extends ConsumerWidget {
                   ),
                   Expanded(
                     child: PrimaryButtonComponent(
+                      loading: state.withoutBackorderLoading,
                       backgroundColor: Colors.red,
                       text: 'Aucun reliquat',
                       onPressed: () async {

lib/pages/operation/reception/reception_details_page_model.dart

@@ -113,6 +113,7 @@ class ReceptionDetailsPageModel
       final createBackorderConfirmationId =
           await ApiCalls.createBackorderConfirmation(
             stockPickingId: receptionId,
+            toBackorder: true,
           );
       if (createBackorderConfirmationId != null) {
         final res = await ApiCalls.withBackorder(
@@ -146,6 +147,7 @@ class ReceptionDetailsPageModel
       final createBackorderConfirmationId =
           await ApiCalls.createBackorderConfirmation(
             stockPickingId: receptionId,
+            toBackorder: false,
           );
       if (createBackorderConfirmationId != null) {
         final res = await ApiCalls.withoutBackorder(