feat: Add isPrivate field to AdminProduct and update filtering logic in admin panels

flutter/lib/features/admin/data/admin_repository.dart

@@ -240,6 +240,7 @@ class AdminRepository {
         name: product.name,
         canonicalName: product.canonicalName,
         ownerId: product.ownerId,
+        isPrivate: true,
         categoryId: product.categoryId,
         categoryPath: product.categoryPath,
         status: 'private',

flutter/lib/features/admin/domain/admin_product.dart

@@ -4,6 +4,7 @@ class AdminProduct {
   final String? canonicalName;
   final String? normalizedName;
   final int? ownerId;
+  final bool? isPrivate;
   final int? categoryId;
   final String? categoryPath;
   final bool? isActive;
@@ -16,6 +17,7 @@ class AdminProduct {
     this.canonicalName,
     this.normalizedName,
     this.ownerId,
+    this.isPrivate,
     this.categoryId,
     this.categoryPath,
     this.isActive,
@@ -46,6 +48,7 @@ class AdminProduct {
       canonicalName: json['canonicalName']?.toString(),
       normalizedName: json['normalizedName']?.toString(),
       ownerId: ((json['owner'] as Map<String, dynamic>?)?['id'] as num?)?.toInt(),
+      isPrivate: json['isPrivate'] as bool?,
       categoryId: (json['categoryId'] as num?)?.toInt(),
       categoryPath: names.isEmpty ? null : names.join(' > '),
       isActive: json['isActive'] as bool?,

flutter/lib/features/admin/presentation/admin_form_shared.dart

@@ -38,13 +38,17 @@ List<AdminProduct> filterSelectableAdminProducts({
   required AdminProduct? selectedProduct,
 }) {
   final ownerFiltered = ownerUserId == null
-      ? products.where((p) => p.ownerId == null).toList()
-      : products.where((p) => p.ownerId == null || p.ownerId == ownerUserId).toList();
+      ? products.where((p) => p.isPrivate != true).toList()
+      : products
+          .where(
+            (p) => p.isPrivate != true || p.ownerId == ownerUserId,
+          )
+          .toList();
 
   final scopeFiltered = switch (scopeFilter) {
     ProductScopeFilter.all => ownerFiltered,
-    ProductScopeFilter.globalOnly => ownerFiltered.where((p) => p.ownerId == null).toList(),
-    ProductScopeFilter.privateOnly => ownerFiltered.where((p) => p.ownerId != null).toList(),
+    ProductScopeFilter.globalOnly => ownerFiltered.where((p) => p.isPrivate != true).toList(),
+    ProductScopeFilter.privateOnly => ownerFiltered.where((p) => p.isPrivate == true).toList(),
   };
 
   final source = categoryId == null
@@ -64,7 +68,7 @@ List<ProductOption> toProductOptions(List<AdminProduct> products) {
       .map(
         (p) => (
           id: p.id,
-          name: p.ownerId == null ? p.displayName : '${p.displayName} (privat)',
+          name: p.isPrivate == true ? '${p.displayName} (privat)' : p.displayName,
           categoryId: p.categoryId,
         ),
       )

flutter/lib/features/admin/presentation/admin_inventory_panel.dart

@@ -854,6 +854,7 @@ class _InventoryFormDialogState extends State<_InventoryFormDialog> {
         name: initial.productName,
         canonicalName: initial.productCanonicalName,
         ownerId: initial.userId,
+        isPrivate: null,
         categoryId: initial.categoryId,
         categoryPath: initial.categoryPath,
         status: 'private',
@@ -943,7 +944,7 @@ class _InventoryFormDialogState extends State<_InventoryFormDialog> {
                       if (value == null) {
                         _productScopeFilter = ProductScopeFilter.globalOnly;
                         final selected = _productById(_productId);
-                        if (selected?.ownerId != null) {
+                        if (selected?.isPrivate == true) {
                           _productId = null;
                         }
                       }

flutter/lib/features/admin/presentation/admin_pantry_panel.dart

@@ -565,6 +565,7 @@ class _PantryFormDialogState extends State<_PantryFormDialog> {
         name: initial.productName,
         canonicalName: initial.productCanonicalName,
         ownerId: initial.userId,
+        isPrivate: null,
         categoryId: initial.categoryId,
         categoryPath: initial.categoryPath,
         status: 'private',
@@ -645,7 +646,7 @@ class _PantryFormDialogState extends State<_PantryFormDialog> {
                     if (value == null) {
                       _productScopeFilter = ProductScopeFilter.globalOnly;
                       final selected = _productById(_productId);
-                      if (selected?.ownerId != null) {
+                      if (selected?.isPrivate == true) {
                         _productId = null;
                       }
                     }